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Question 1 Report
In vascular plants, xylem tissue is responsible for
Answer Details
In vascular plants, the xylem tissue is primarily responsible for the transportation of water. The xylem functions like a network of tubes spreading throughout the plant, from the roots up to the leaves. Its main role is to carry water and dissolved minerals absorbed from the soil by the roots to other parts of the plant. This movement of water is crucial for maintaining plant health as it supports essential processes like photosynthesis and nutrient distribution. Unlike other tissues, xylem is specifically adapted for this task, with its elongated, tube-like structures which provide an effective passage for water movement.
Question 2 Report
One of the characteristics of secondary succession is that it
Answer Details
Secondary succession is a process that occurs when an ecosystem that has already been colonized by living organisms is disturbed, but the soil and some of its organisms remain intact. This can happen after events such as forest fires, hurricanes, or human activities like farming. In contrast to primary succession, secondary succession does not start from scratch or a barren surface.
The characteristic of secondary succession is that it starts on an already colonized surface. This means that the area had life before but was disturbed, so the succession process is somewhat quicker since the soil contains seeds, nutrients, and microorganisms that speed up the recovery of the ecosystem. This contrasts with primary succession, which starts on bare and barren surfaces, like rocks or volcanic lava fields, where soil needs to form first.
Question 3 Report
Comparative anatomy to study evidence for evolution depends on
Answer Details
**Comparative anatomy** involves studying the similarities and differences in the anatomy of different species. One of its main purposes in understanding **evolution** is to trace how organisms are related through common ancestry. When we look at the limbs of different animals, some specific features provide essential evidence for evolution.
A key feature often examined is the structure of the limbs of vertebrates, which have evolved to adapt to different environments and modes of living, but share a basic underlying structure. This shared structure is often referred to as the **pentadactyl limb** pattern. The term "pentadactyl" means **five-fingered** or having five digits.
In many vertebrates like humans, whales, bats, and so forth, this **five-fingered** limb structure can be observed, although it has evolved to perform different functions in each species. For example, a human hand, a bat's wing, and a whale's flipper all have the same basic arrangement of bones. This points to the fact that these species share a **common ancestor** and have evolved differently as they adapted to their environments.
Thus, comparative anatomy's focus on the **five-fingered** pattern in limbs is crucial as it provides **evidence** of evolutionary relationships among diverse species, illustrating how they have evolved from a shared ancestry.
Question 4 Report
The bacteria in the large intestine of man synthesizes
Answer Details
The large intestine of humans is home to a diverse community of beneficial bacteria. These bacteria primarily synthesize vitamins, particularly vitamin K and some of the B vitamins, such as B12. They do not typically produce minerals or glucose.
Here's a simple breakdown:
Thus, the correct and simplest answer is that the bacteria in the large intestine primarily synthesize vitamins.
Question 5 Report
Body temperature, thirst and hunger are regulated by
Answer Details
The regulation of body temperature, thirst, and hunger is primarily managed by the hypothalamus. This is a small but crucial part of the brain located just below the thalamus. It plays a key role in maintaining the body's internal balance, known as homeostasis.
Here is a simple breakdown of its functions:
The hypothalamus achieves these regulations by interacting with the endocrine system, releasing hormones that affect various bodily functions. So, if you are thinking of which area of the brain is in charge of these vital processes, the answer is indeed the hypothalamus.
Question 6 Report
Use the diagram above to answer the question that follows:
Recombination of genes at fertilization is represented by the part labelled
Answer Details
During prophase I, homologous chromosomes from each parent pair up and exchange genetic material, a process known as crossing over. This process creates new combinations of genes in the resulting gametes. When two gametes unite during fertilization, the offspring will have a unique combination of DNA.
Genetic recombination during fertilization takes place in the prophase I stage of meiosis ( part labelled III)
Question 7 Report
The rhizoid of liverwort is
Answer Details
The rhizoid of liverwort is unicellular and unbranched.
Here's a simple explanation: Liverworts are a type of non-vascular plant that have structures called rhizoids. These rhizoids look like tiny hairs and they help the plant attach to surfaces like rocks or soil. Even though they help with attachment, they do not have the complexity of true roots.
In liverworts, these rhizoids are formed as single cells, which means they are unicellular. Think of them as being like a single long cell that looks like a hair. This single-celled structure is unbranched, meaning it doesn't split or divide into more parts or sections.
In summary, liverwort rhizoids are unicellular and unbranched, helping them secure the plant to various surfaces without forming complex root structures.
Question 8 Report
A discontinuous morphological variation often used in crime detection is the
Answer Details
In crime detection, the most popular discontinuous morphological variation used is finger prints.
Here's a simple way to understand why:
Defining Morphological Variation: Morphological variation refers to differences in the form and features of living organisms. A variation is termed as 'discontinuous' when it falls into distinct categories with no intermediates. For example, you either have a particular feature or you don't.
Why Fingerprints are Discontinuous: Fingerprints are a good example of discontinuous variation because each individual's set of fingerprints is unique. There are no gradual transitions – you either have a specific fingerprint pattern, like a loop, whorl, or arch, or you don't.
Application in Crime Detection: Because everyone has a unique set of fingerprints and these can be easily left on surfaces, fingerprints are a powerful tool in crime detection. Investigators gather fingerprint evidence from crime scenes and compare them with fingerprint databases to identify suspects.
In conclusion, the use of fingerprints lies mainly in their uniqueness and distinctiveness, making them crucial for identifying individuals in forensic investigations.
Question 9 Report
The pigment carrying oxygen in the blood is
Answer Details
The pigment responsible for carrying oxygen in the blood is haemoglobin. Haemoglobin is a complex protein found in red blood cells. Its primary function is to transport oxygen from the lungs to the rest of the body and return carbon dioxide from the body to the lungs for exhalation. Each haemoglobin molecule can bind to four oxygen molecules, allowing it to carry and efficiently distribute a large amount of oxygen throughout the body.
Here's a simple explanation of how it works:
It is essential to note that while oxyhaemoglobin is simply haemoglobin that has combined with oxygen, the fundamental oxygen-carrying pigment itself is still haemoglobin.
Question 10 Report
Which of these is a medium of transportation in plants?
Answer Details
In plants, the **medium of transportation** is primarily the **cell sap**. Cell sap is the liquid found inside the large central vacuole of plant cells, and it plays a key role in transporting nutrients, minerals, and waste products. The vacuole itself is an important component in maintaining cell turgor pressure, which helps keep the plant upright. The movement of cell sap helps distribute essential substances throughout the plant.
On the other hand, the other options do not serve as media for transportation in plants:
Therefore, for transportation within plants, the **cell sap** is the correct answer.
Question 11 Report
I
6 X + 6 H2 O → C6 H12 O6 + 6O2
III chlorophyll II IV
Use the diagram above to answer question that follows
The part labelled I is
Answer Details
The part labelled I in the given equation refers to sunlight.
Here is why:
The equation you've provided represents the chemical process of photosynthesis, which is how plants convert light energy into chemical energy stored in glucose (C6H12O6). This process occurs in the chloroplasts of plant cells.
Sunlight is essential in this process because it provides the energy needed for photosynthesis to occur. This process begins when chlorophyll (labelled as III) within the chloroplasts absorbs sunlight, enabling the transformation of carbon dioxide (CO2) and water (H2O) into glucose and oxygen (O2).
In summary, the part labelled I is sunlight because it is the energy source that drives the entire reaction of photosynthesis.
Question 12 Report
Use the diagram above to answer the question that follows
The endocrine gland that is located in the part labelled I is
Answer Details
The endocrine gland located in the part labelled 'I' is the pituitary gland.
The pituitary gland is a small, pea-sized gland located at the base of the brain, just below the hypothalamus, which connects to it. It is often referred to as the "master gland" because it plays a crucial role in regulating a wide variety of bodily functions by secreting hormones that control other glands in the endocrine system, such as the thyroid, adrenal glands, and reproductive organs.
Key Points:
Question 13 Report
Answer Details
The first organisms on Earth are widely believed to have evolved from aquatic habitats. This conclusion is based on several scientific observations and theories.
1. **Early Earth Conditions:** When Earth was still a young planet, conditions were harsh, with a very hot climate and volcanic activity. During this time, the planet's surface was largely covered by oceans which provided a stable environment where simple life forms could potentially thrive. The presence of water is essential because it acts as a medium for chemical reactions and life-supporting processes.
2. **Chemistry of Life:** Water is a solvent that facilitates the necessary chemical reactions required for life. In aquatic environments, organic molecules could dissolve in water, leading to complex chemical reactions, leading to the formation of proteins, lipids, and nucleic acids, which are building blocks of life.
3. **Abiogenesis and the "Primordial Soup" Theory:** One theory of how life began is called the "primordial soup" theory, which suggests that life originated through chemical reactions in the ocean. This soup-like mixture of organic compounds provided the ideal conditions for the first living organisms to form.
4. **Evidence from Fossils:** The oldest known fossils are those of simple microorganisms such as bacteria. These fossils have been found in ancient sedimentary rocks, which were formed in water.
In summary, while there are different types of habitats available on Earth now, the initial conditions billions of years ago favored the formation of life in an aquatic environment. Therefore, it is widely accepted that the earliest life forms evolved in the aquatic habitat.
Question 14 Report
Blood group AB is considered as universal recipient because they can receive blood from groups
Answer Details
Blood group AB is considered a universal recipient because individuals with this blood type can receive blood from all other blood groups, including A, B, AB, and O. This is possible due to the presence of both A and B antigens on the surface of their red blood cells and the absence of anti-A and anti-B antibodies in their plasma.
Here’s a simple breakdown:
This makes AB blood group the universal recipient as they can accept A, B, AB, and O blood, without experiencing adverse reactions caused by antibody-antigen incompatibility.
Question 15 Report
Use the diagram above to answer the question that follows
The experiment is set up to determine the presence of
Answer Details
Chlorophyll: Experiments related to chlorophyll typically involve leaves and light exposure to understand photosynthesis. You might see diagrams showing a leaf that is partially covered with foil to demonstrate which parts of the leaf perform photosynthesis.
Starch: To test for the presence of starch, particularly in plants, an experiment usually involves boiling a leaf in water, then in alcohol, and finally treating it with iodine solution. The presence of starch is confirmed by a blue-black color change.
Oxygen: Experiments designed to detect oxygen often involve aquatic plants like Elodea. When the plant is exposed to light, bubbles or gases released would indicate photosynthetic activity, releasing oxygen.
Pigment: Pigment experiments often relate to chromatography, where pigments are separated on a medium like paper. These are used to study various pigments present within plant tissues.
Question 16 Report
Loamy soil is characterized by
Answer Details
Loamy soil is characterized by a distinct combination of features that make it particularly favorable for plant growth. It contains a balanced mixture of three types of soil particles: sand, silt, and clay. This combination gives loamy soil its unique properties.
High Humus: Loamy soil is known for having a high content of organic matter, often referred to as humus. Humus is important because it improves soil fertility, provides vital nutrients for plants, and helps retain moisture.
Moderate Porosity: Loamy soil has a structure that provides moderate porosity. This means it can hold water effectively while also allowing excess water to drain away, ensuring that plants have both the water and air they need. It balances water retention and aeration very well.
Because of these characteristics, loamy soil is considered one of the best soils for agriculture and gardening. Therefore, the description that best characterizes loamy soil is high humus and moderate porosity.
Question 17 Report
The type of variation where there are no remarkable differences between the two extreme individuals is called
Answer Details
The type of variation where there are no remarkable differences between the two extreme individuals is called continuous variation.
In biology, variation refers to the differences among individuals within a population. When we refer to continuous variation, we're talking about traits that are measured on a scale and show a range of small differences between individuals. An example is human height or weight. In these cases, individuals do not fall into a finite or distinct number of categories, but rather display a smooth and gradual transition across a range.
This type of variation typically results from the combined effects of many genes (polygenic inheritance) and the influence of environmental factors. It presents as a continuous range of expression, forming a bell-shaped curve when graphed, rather than discrete categories. Because of this smooth transition without sharp differences, it's termed as continuous variation.
Question 18 Report
One of the ways of controlling Schistosomiasis is by
Answer Details
One effective way of controlling Schistosomiasis is by destroying water snails and water weeds.
Schistosomiasis, also known as bilharzia, is a parasitic disease caused by trematode worms of the genus Schistosoma. The life cycle of these parasites heavily involves freshwater snails, which act as intermediate hosts. Here's how the life cycle works:
By destroying water snails and eliminating water weeds, which can provide habitat for these snails, you interrupt the lifecycle of the parasite. This can significantly reduce the risk of transmission to humans. It is crucial to control snail populations in freshwater bodies where human contact is common.
This method, along with other control measures such as providing access to safe water, improving sanitation, and educating communities about safe water practices, plays a crucial role in reducing schistosomiasis transmission. Importantly, to combat the disease effectively, a combination of approaches is usually necessary.
Question 19 Report
Which of the following characteristics is possessed by both living and non-living things?
Answer Details
In considering the given options, the characteristic that is possessed by both living and non-living things is that they both have weight.
Here is the simple explanation:
Therefore, the characteristic of having weight is shared by both living and non-living things.
Question 20 Report
The part of the brain that receives sensory impulses of smell is the
Answer Details
The part of the brain that receives sensory impulses of smell is the olfactory lobe. When you perceive a scent, information from the nose's sensory cells is sent to the olfactory lobe, and it is here that the brain begins the process of identifying the fragrance. The olfactory bulb is the first region that processes smell sensory data, allowing you to discern various odors. Other parts of the brain, like the cerebrum, help process and associate these smells with memories or emotions, but the olfactory lobe is the initial receiver of these sensory signals related to smell.
Question 21 Report
The process by which plants loss water to the atmosphere is
Answer Details
The process by which plants lose water to the atmosphere is referred to as transpiration. Let's break this down:
Transpiration is the process where water absorbed by plant roots is eventually released into the atmosphere as water vapor through the plant's leaves. This primarily occurs through small openings on the leaves known as stomata.
Here's how it happens:
Transpiration is crucial for plants because it not only helps them get rid of excess water but also plays a significant role in cooling the plant and enabling the upward movement of essential nutrients from the soil. It also contributes to the water cycle by adding moisture to the atmosphere.
In summary, transpiration is an essential process where plants lose water to the atmosphere, playing an important role in plant health and environmental equilibrium.
Question 22 Report
The transmission of diseases through contamination of food is an economic importance of
Answer Details
The transmission of diseases through contamination of food is an economic importance primarily related to cockroaches.
Cockroaches are considered pests that thrive in unsanitary environments. They are known to carry various pathogens, such as bacteria, viruses, and parasites, on their bodies and in their droppings. When they come into contact with food, they can contaminate it, leading to foodborne diseases.
This contamination can have several economic impacts:
Therefore, managing and preventing cockroach infestations is crucial to safeguarding public health and protecting economic interests associated with food safety.
Question 23 Report
The cells responsible for transmitting messages to the effectors are
Answer Details
The cells responsible for transmitting messages to the effectors are motor neurons. These neurons play a critical role in the nervous system by transmitting impulses from the central nervous system (such as the brain and spinal cord) towards the muscles and glands, which are collectively known as effectors.
Here's a simple breakdown of how this process works:
Effectors are essential as they perform actions in response to neural signals, making motor neurons integral in generating coordinated movement and various physiological responses. In contrast, sensory neurons carry information from sensory receptors to the central nervous system, relay neurons (interneurons) facilitate communication within the central nervous system, and hair cells are specialized sensory receptors in the auditory and vestibular systems. Thus, the primary role of motor neurons is to convey signals to effectors to initiate a response or action.
Question 24 Report
In which zone of the marine habitat does the organisms require adaptation for attachment?
Answer Details
The marine habitat is divided into various zones, each with its own environmental conditions and challenges for the organisms living there. Among these zones, the intertidal zone is the one where organisms require significant adaptation for attachment. The intertidal zone is the area that is exposed to the air at low tide and submerged under water at high tide.
The main reasons organisms need adaptations for attachment in this zone are:
Therefore, the intertidal zone specifically requires organisms to have adaptations that ensure they remain securely attached despite the dynamic and challenging conditions encountered daily.
Question 25 Report
How many chromosomes will be present in a gamete if the somatic cell has 8 chromosomes?
Answer Details
In humans and many other organisms, there are two types of cells: **somatic cells** and **gametes**. **Somatic cells** are typical body cells and are **diploid**, meaning they contain two sets of chromosomes—one set from each parent. **Gametes** are reproductive cells (sperm and egg) and are **haploid**, meaning they contain only one set of chromosomes.
In this context, if a **somatic cell** has **8 chromosomes**, it means it is carrying two complete sets of 4 chromosomes each. In order to form a **gamete**, this diploid number must be reduced to a **haploid number** through the process of **meiosis**.
Therefore, the **number of chromosomes** in a **gamete** would be **half** the number of chromosomes in a **somatic cell**. This is because gametes need to have just one set of chromosomes to ensure that when two gametes meet during fertilization, they create a diploid organism.
Thus, if the **somatic cell** has **8 chromosomes**, each **gamete** will have **4 chromosomes**.
Question 26 Report
After fertilization in plants, the zygote develops into
Answer Details
After fertilization in plants, the zygote develops into an embryo. This process is a critical stage in the life cycle of a plant. Let me explain it in simple steps:
Therefore, after fertilization, the focus on growth centers around the development of the embryo, which is a crucial step in the successful reproduction and life cycle continuation of plants.
Question 27 Report
Bile is a greenish alkaline liquid which is stored in the
Answer Details
Bile is a greenish alkaline liquid that plays a crucial role in the digestion of fats. It is produced by the liver and contains bile acids, which are essential for emulsifying fats, making them easier for enzymes to break down. Once bile is produced by the liver, it is not immediately released into the digestive tract. Instead, it is stored and concentrated in the **gall bladder**. The gall bladder is a small, pouch-like organ located just beneath the liver. It stores bile until it is needed, typically after eating, when it is then released into the small intestine to aid in digestion.
Question 28 Report
The formation of cilia and flagella in living cells is carried out with the help of
Answer Details
The formation of cilia and flagella in living cells is primarily carried out with the help of centrioles.
In eukaryotic cells, cilia and flagella are long, hair-like structures that extend from the surface of the cell and are responsible for movement. They are made up of microtubules, which are protein structures. The base of a cilium or a flagellum is anchored to a cell by a structure called the basal body.
The basal body is very similar in structure to a centriole. Centrioles are cylinder-shaped organelles found in animal cells and are composed of microtubule triplets. When a cell is ready to produce cilia or flagella, the centrioles migrate to the surface of the cell and become basal bodies by aiding in the assembly and organization of these microtubules.
Therefore, the role of centrioles is crucial because they act as the organizing centers for the microtubule structures that comprise cilia and flagella. Without centrioles, a cell would not be able to form these important structures.
Question 29 Report
A community with a population of two million three hundred and ten thousand people living in an area of two thousand three hundred and ten square kilometres has a population density of
Answer Details
To calculate the population density of a region, you need to divide the **total population** by the **area** they are living in. This will give you the number of people per unit area, typically per square kilometer in this case.
Given:
The formula for population density is:
Population Density = Total Population / Area
By plugging in the given values:
Population Density = 2,310,000 / 2,310 = 1,000
This means there are **1,000 people per square kilometer** in this community. Therefore, the correct population density is **1,000**.
Question 30 Report
The endocrine gland that is called the master gland is the
Answer Details
The **pituitary gland** is known as the **"master gland"** of the endocrine system. Let us explore why this is important in a simple way.
The pituitary gland is a tiny, pea-sized organ located at the base of the brain, right behind the bridge of the nose. Despite its small size, it plays a crucial role in regulating vital body functions and general wellbeing.
Why is it called the master gland?
In summary, the pituitary gland is termed the "master gland" because it has the ability to control many other glands within the endocrine system, playing a pivotal role in maintaining the body's environment or homeostasis.
Question 31 Report
The common examples of trees found in the desert are
Answer Details
Deserts are characterized by their arid conditions, meaning they receive very little rainfall throughout the year. To survive in such environments, plants need special adaptations. Among the plant varieties, the trees commonly found in deserts include **cacti** and the **baobab tree**. Here's a brief explanation of why these trees are well-suited to desert environments:
Plants like **raffia palm**, **coconut**, **white and red mangrove**, and **shea-butter** trees are not typically found in desert environments because they require more moisture and different soil conditions compared to the harsh, dry lands of the desert.
Question 32 Report
Infectious diseases are caused by
Answer Details
Infectious diseases are illnesses caused by certain harmful microorganisms that invade the body. These microorganisms can be grouped into several categories. Among these categories, two of the most notable are bacteria and protozoa. Both of these groups contain species that can lead to disease.
Bacteria are single-celled microorganisms. While many bacteria are harmless or even beneficial to humans, some can cause diseases such as strep throat, tuberculosis, and urinary tract infections. Bacteria are living organisms that reproduce by themselves, and they can sometimes produce toxins that harm the host.
Protozoa are a diverse group of single-celled organisms that live in a variety of moist or aquatic environments. Many protozoa are harmless, but some can cause serious diseases. For example, the protozoan parasite Plasmodium causes malaria, a serious disease transmitted by mosquitoes.
Protists is a broader term that includes protozoa as well as algae and fungi-like organisms, and while not all protists cause disease, the term could refer to certain disease-causing protozoans.
Amoebas are a type of protozoan characterized by their changing shape and movement. Although many amoebas are harmless, some types, such as Entamoeba histolytica, cause illnesses like amoebic dysentery, which is characterized by diarrhea and stomach pain.
In summary, infectious diseases can be caused by bacteria and a variety of protozoa, including specific types like amoebas. Understanding these different microorganisms helps in diagnosing and treating the diseases they cause.
Question 33 Report
A common component of blood and lymph is
Answer Details
Blood and lymph are both crucial components of the circulatory and immune systems in the body. One of the key components that is common to both blood and lymph is the white blood cell. Here's how:
White blood cells, also known as leukocytes, play a significant role in defending the body against infections, diseases, and foreign invaders. They are an essential part of the immune system.
In blood, white blood cells circulate through the cardiovascular system and help in identifying and attacking pathogens like bacteria, viruses, and other harmful microorganisms.
In lymph, white blood cells are found in the lymphatic fluid and lymph nodes, where they help filter and trap pathogens, preventing them from spreading further into the body.
Therefore, white blood cells are the common component of both blood and lymph, playing a crucial role in the body's defense mechanisms.
Question 34 Report
Bryophyte is an intermediate group between higher algae and
Answer Details
Bryophytes are an intermediate group between higher algae and pteridophytes. Let's break this down to understand why.
Bryophytes include plants like mosses and liverworts. They are often referred to as the simplest form of land plants because they are non-vascular, meaning they do not have specialized tissues, like xylem and phloem, for water and nutrient transport. Instead, they rely on diffusion, which limits their size and requires them to live in moist environments.
On the other hand, pteridophytes are a group of plants that include ferns and are the next step up in complexity from bryophytes. They are important in this context because they mark the transition from non-vascular bryophytes to vascular plants (plants with vascular systems).
Why is this important? This transition is crucial because it represents the evolution of plants from simple, water-dependent organisms to more complex and diverse forms that can live in a wider range of environments, thanks to their vascular systems.
In summary, bryophytes serve as an evolutionary bridge between the simpler algae and the more complex pteridophytes due to their similarities and differences in structure and reproduction.
Question 35 Report
An example of organism that exhibits counter-shading to escape from its predator is
Answer Details
An example of an organism that exhibits counter-shading to escape from predators is a fish. Counter-shading is a type of camouflage where an animal has a darker coloration on its upper side and a lighter coloration on its underside.
This adaptation helps fish in two main ways:
This dual blending effect helps fish to reduce the risk of being detected by predators, enhancing its chances of survival. This strategy is particularly beneficial in open water habitats where there are few places to hide.
Question 36 Report
A fruit formed from one flower with many carpels is referred to as
Answer Details
A fruit formed from one flower with many carpels is referred to as an aggregate fruit.
Let me break that down further for clarity: When a single flower contains multiple ovaries (carpels), each of these ovaries can develop into a small fruit. These small fruits collectively form what is known as an aggregate fruit. This means that although the fruit appears to be one single entity, it is actually made up of many small fruits that are clustered together. Each small fruit in the cluster originates from a single ovary of the flower.
An example of an aggregate fruit is a raspberry or a blackberry, where the clustered small fruits can easily be observed.
Question 37 Report
Mouth part adapted for piercing and sucking is found in
Answer Details
The mouth parts adapted for piercing and sucking are found in the mosquito. Mosquitoes have specialized mouthparts known as a proboscis, which is designed to pierce the skin of their hosts and suck blood. This proboscis consists of a long, slender, and flexible tube that can penetrate the skin. Inside the proboscis are several delicate structures that help to hold the host's skin and locate blood vessels, allowing the mosquito to efficiently feed on blood.
In contrast, insects like the housefly have sponge-like mouthparts for lapping up liquids, the grasshopper has chewing mouthparts adapted for eating plants, and the cockroach also has chewing mouthparts suitable for a wide range of foods.
Question 38 Report
A succession that occurs in an area where there are no pre-existing community is called
Answer Details
A succession that occurs in an area where there is no pre-existing community is called Primary Succession.
To understand this, imagine a barren landscape where life has never existed before, such as a newly formed volcanic island or a region uncovered by a retreating glacier. In such places, there are no soils or organisms present initially. Here’s how it happens:
In summary, primary succession describes the process of life gradually establishing itself from scratch in an environment that starts with no life or soil, forming an ecosystem over time.
Question 39 Report
In glycolysis, glucose is broken down through series of reactions in the presence of enzyme and absence of oxygen to produce
Answer Details
Glycolysis is a biochemical process through which glucose, a six-carbon sugar, is broken down into two molecules of a three-carbon compound called **pyruvic acid** or **pyruvate**. This process occurs in the **absence of oxygen** and is also referred to as anaerobic respiration. During glycolysis, energy stored in glucose is released, and a net gain of **two molecules of ATP (adenosine triphosphate)** is produced, which serves as a direct energy source for cellular activities.
Here is a brief explanation of the main steps involved in glycolysis:
In summary, during glycolysis in the absence of oxygen, glucose is transformed into **pyruvic acid and a net gain of ATP molecules**, making the answer **pyruvic acid + ATP**.
Question 40 Report
Which of the following processes releases oxygen to the atmosphere?
Answer Details
In the context of releasing oxygen to the atmosphere, only one of the processes you've listed does this: photosynthesis. Let me explain it in a simple way.
Photosynthesis is a process carried out by plants, some bacteria, and algae. These organisms use sunlight, carbon dioxide, and water to create their food, which is a form of sugar. As a byproduct, they release oxygen into the atmosphere. During this process, chlorophyll, the green pigment in plant cells, captures light energy, and helps convert it into chemical energy.
None of the other processes release oxygen:
- Respiration is a process in which living organisms, including plants and animals, take in oxygen and use it to convert glucose into energy, producing carbon dioxide and water as byproducts.
- Combustion involves burning substances, typically in the presence of oxygen, usually resulting in the production of carbon dioxide, water, and energy (heat and light). It does not release oxygen; rather, it consumes oxygen.
- Decomposition is the breakdown of dead organic matter by microorganisms. During this process, organic matter is converted back into carbon dioxide, methane, and other compounds, but it does not release oxygen.
So, the process that releases oxygen into the atmosphere is photosynthesis.
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