JAMB UTME - Biology - 2017

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Variation, in biology, any difference between cells, individual organisms, or groups of organisms of any species caused either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation).

Variation may be shown in physical appearance, metabolism, fertility, mode of reproduction, behaviour, learning and mental ability, and other obvious or measurable characters.

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Cohesion is an ability of water molecule to stick to one another due to the presence of hydrogen bonding

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The protista that is a producer in an aquatic food chain is called "Chlamydomonas". Chlamydomonas is a unicellular organism that belongs to the kingdom Protista and is commonly found in freshwater environments such as ponds and lakes. It is a type of algae that performs photosynthesis, which means that it uses energy from sunlight to produce its own food. In an aquatic food chain, Chlamydomonas plays a vital role as a primary producer. It provides energy and nutrients to other organisms in the food chain, such as small aquatic animals like zooplankton, which in turn are eaten by larger predators like fish. Without Chlamydomonas and other primary producers, the food chain would collapse and the entire ecosystem would be negatively affected.

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The lungs of the lungfish are an adaptation for respiration while on land. Lungfish are a unique group of fish that can survive in both water and on land. While in water, they use their gills to extract oxygen from the water, but when they are on land, they use their lungs to extract oxygen from the air. This ability to use both gills and lungs makes lungfish well adapted to survive in environments where water availability can fluctuate, such as in shallow waters or temporary ponds that may dry out seasonally. Thus, the lungs of lungfish are an important adaptation for respiration while on land, allowing them to breathe air and survive in their changing aquatic environments.

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Nitrogen is essential to all living systems, which makes the nitrogen cycle one of Earth's most important nutrient cycles.

Atmospheric nitrogen becomes part of living organisms in two ways. The first is through bacteria in the soil that form nitrates out of nitrogen in the air. The second is through lightning. During electrical storms, large amounts of nitrogen are oxidized and united with water to produce an acid that falls to Earth in rainfall and deposits nitrates in the soil.

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Food chain refers to the sequence of transfers of matter and energy in the form of food from organism to organism. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. Plants, which convert solar energy to food by photosynthesis, are the primary food source. In a predator chain, a plant-eating animal is eaten by a flesh-eating animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by even smaller organisms.

In a saprophytic chain, microorganisms live on dead organic matter.

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Red blood cells are also known as erythrocytes. Erythrocytes are cells in the blood that are responsible for carrying oxygen from the lungs to the rest of the body, and for carrying carbon dioxide from the body to the lungs to be expelled. They are shaped like disks and have a flexible structure, allowing them to move easily through the narrowest blood vessels. They also contain a protein called hemoglobin, which binds to oxygen and gives red blood cells their characteristic red color.

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Amphibians display some interesting and changing characteristics as they metamorphose through various forms on their way to adulthood. The frog, for instance, begins life underwater as a larva with gills and becomes and air-breather with lungs as an adult.
&therefore4; in case of draught, frog can amphibians can use lungs to breathe on land

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A bacteria that is spherically shaped is called a coccus. Bacteria can come in different shapes, and the shape of a bacterium is used to classify it into different groups. Coccus is a type of bacteria that is rounded or spherical in shape. Examples of coccus bacteria include Staphylococcus, which can cause skin infections, and Streptococcus, which can cause strep throat and other illnesses.

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The modification in structure, physiology and behaviour of plant and animal is called adaptation. Adaptation refers to the changes that occur in living organisms in response to the challenges presented by their environment. These changes can be physical, such as the development of longer legs or sharper claws, or behavioral, such as the development of new hunting strategies or social behaviors. Adaptations can occur over short periods of time, such as within the lifetime of an individual organism, or over longer periods of time, such as across multiple generations. The process of adaptation allows organisms to survive and thrive in their environments, and is a key mechanism of evolution, the process by which species change over time.

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The scenario that would cause a covalent bond to form is when two atoms share electrons so they can fill their outer shells. In a covalent bond, atoms share electrons to achieve a stable electron configuration, which means having a complete outermost energy level. This sharing of electrons allows both atoms to have a full outer shell, making them more stable and less likely to react with other atoms. Covalent bonds are typically formed between non-metal atoms, as they tend to have a greater affinity for electrons and are more likely to share them with other atoms.

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The clumping of cells such as bacteria or red blood cells in the presence of an antibody or complement.

During blood transfusions, the antibodies react with the transfused blood group(if its of different blood group), the erythrocytes clump up and stick together causing them to agglutinate

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When an ovary is placed on the receptacle above the other floral parts, it is referred to as a "superior ovary". In a flower, the ovary is the part that contains the ovules, which will develop into seeds after fertilization. The ovary is typically located at the base of the flower, below the other floral parts like the petals, sepals, and stamens. In some flowers, however, the ovary is situated on top of the receptacle, which is the part of the stem that supports the flower. This type of ovary is called a "superior ovary". It is said to be superior because it is located above the other floral parts. This arrangement of the ovary can have implications for the structure of the rest of the flower. For example, if the petals, sepals, and stamens are attached to the receptacle below the ovary, they are said to be "epigynous". If they are attached to the receptacle above the ovary, they are said to be "hypogynous". These terms refer to the relative positions of the floral parts and can be used to describe the overall structure of the flower.

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Liver fluke (Fasciola hepatica) is a parasite affecting a range of livestock and other species. Final hosts in which it can develop to sexual maturity include livestock such as sheep, cattle, horses, pigs, goats, alpacas and deer. People can be infected by eating water cress growing along creeks in fluke-infested country

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The characteristic of bacteria that does not fit with the others listed is "they do not cause disease." Bacteria are unicellular microorganisms that can be seen under a microscope. They vary in size, but most range from 0.5 µm to 5 µm in diameter. Bacteria can be grouped according to their cell shape, which can be cocci (spherical), bacilli (rod-shaped), or spirilla (spiral-shaped). While some bacteria can cause disease, not all bacteria are harmful. In fact, many types of bacteria are beneficial and essential for human and environmental health. For example, some bacteria help with digestion, while others are used to break down waste materials. Therefore, it is incorrect to assume that all bacteria are disease-causing organisms.

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Eye coloration is a caused by morphological variation

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The knee joint is one of the strongest and most important joints in the human body. It allows the lower leg to move relative to the thigh while supporting the body’s weight.

Movements at the knee joint are essential to many everyday activities, including walking, running, sitting and standing.

The knee, also known as the hinge joint(tibiofemoral joint) formed between three bones: the femur, tibia, and patella.

A gliding joint, also known as a plane joint or planar joint, is a common type ofjoint formed between bones that meet at flat or nearly flat articular surfaces.

Pivot joint, also called rotary joint is a freely moveable joint that allows only rotary movement around a single axis. Pivot joints also provide for the twisting movement of the bones of the forearm (radius and ulna) against the upper arm.

The ball and socket joint (or spheroidal joint) is a type of synovial joint which enables the bone to move in many places (nearly all directions). These are found in the hip.

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Morphological variation includes aspects of the outward appearance i.e shape, structure, color, pattern, size which is in contrast to physiology variation which deals primarily with function.

Morphological variation arises from a number of factors which can be bluntly classified as either genetic or environmental implanted into the process of evolution.

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An anemometer is a device used for measuring wind speed, and is also a common weather station instrument.

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It should be Anemometer, which is used to measure the speed of wind

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The level of organization in Spirogyra and Volvox is cell. Spirogyra is a type of green algae that consists of long, thin, spirally coiled filaments. Each filament is made up of many individual cells. Volvox is a type of green algae that forms spherical colonies. The colonies are made up of many individual cells that are organized into a multicellular structure. Both Spirogyra and Volvox are examples of organisms that are made up of individual cells. They do not have tissues or organs, which are structures made up of multiple cells that perform specific functions. They also do not have systems, which are groups of organs that work together to perform a particular function.

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The biome that is characterized by large herbivores, few and scattered fire-resistant trees is the savanna. Savannas are grasslands with scattered trees. They are found in many parts of the world, including Africa, South America, and Australia. Large herbivores, such as zebras, elephants, and giraffes, roam the savanna and feed on the grass. The few trees that grow in the savanna are often fire-resistant, meaning they can survive fires that occur naturally in the area. The combination of grass and scattered trees makes the savanna a unique and important ecosystem.

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The first stage of incomplete metamorphosis is the egg. During this time, the insect will hatch into a form called a nymph.

The nymph is basically a small version of the adult insect.

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In mosses, the structure that performs the function of water absorption is the rhizoids. Rhizoids are thin, hair-like structures that grow from the lower surface of the moss and penetrate into the soil or substrate. They do not have the specialized tissues that are found in true roots, such as root hairs, but they function in a similar way by absorbing water and minerals from the environment. Rhizoids also help to anchor the moss to its substrate, preventing it from being swept away by wind or water.

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The most efficient respiratory structure used by free-living protozoa is the body surface. Protozoa are single-celled organisms that are found in a variety of habitats, including freshwater, marine environments, and soil. They need to take in oxygen in order to survive, just like multicellular organisms. The body surface of a protozoan is covered in tiny, hair-like projections called cilia, which create a current of water over the surface of the cell. This current helps to bring oxygen-rich water into contact with the protozoan's body, allowing it to diffuse across the cell membrane and into the cell where it can be used for respiration. This method of respiration is efficient because it takes advantage of the large surface area of the protozoan's body, which allows for a large amount of oxygen to be absorbed. Additionally, the constant movement of the cilia helps to maintain a constant flow of oxygen-rich water over the surface of the cell, ensuring that the protozoan has a continuous supply of oxygen.

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Erythrocytes are known as red blood cells. They are called red blood cells because they contain a red pigment called hemoglobin which binds to oxygen and gives blood its red color. Erythrocytes are responsible for carrying oxygen from the lungs to the body's tissues and organs, and they also help transport carbon dioxide from the tissues back to the lungs to be exhaled. Unlike white blood cells (leucocytes) and phagocytes, erythrocytes do not play a direct role in the immune system.

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Plant build of of organic compounds such as oil, coal and gas is a great source of emission of carbon dioxide into the atmosphere
Human activities such as the burning of oil, coal and gas, as well as deforestation are the primary cause of the increased carbon dioxide concentrations in the atmosphere.
Other source such has respiration by animals, thunderstorm release carbon dioxide in smaller quantities compare to 87% of carbon dioxide emission from plants build-up organic compounds through human activities

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The correct choice is "contains lipids and proteins." The cell membrane is the outermost layer of the cell that separates the internal environment of the cell from the external environment. It is composed mainly of two types of molecules: lipids and proteins. The lipids in the cell membrane are primarily phospholipids, which have a hydrophilic (water-loving) head and a hydrophobic (water-fearing) tail. These lipids are arranged in a bilayer, with the hydrophobic tails facing each other and the hydrophilic heads facing outward towards the watery environments on either side of the membrane. The proteins in the cell membrane serve a variety of functions, including transport of molecules across the membrane, cell signaling, and structural support. Some proteins span the entire membrane, while others are only present on one side. The cell membrane also contains small amounts of carbohydrates and other molecules, but lipids and proteins are the two main components.

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Gregor Mendel is regarded as the father of genetics. Mendel was a monk who conducted experiments with pea plants in the mid-19th century. He discovered that certain traits, such as the color of a pea or the height of a plant, are determined by "factors" that are passed down from parent to offspring. These factors are now known as genes, which are made up of DNA and serve as the basic units of heredity. Mendel's experiments and observations led him to formulate the laws of inheritance, which describe how genes are passed down from generation to generation. His work laid the foundation for modern genetics and helped establish the idea that traits are determined by specific genes. Mendel's discoveries had a profound impact on the scientific community and are now recognized as one of the most important breakthroughs in the history of biology. As a result, he is commonly referred to as the father of genetics.

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The host of Taenia solium, also known as the pork tapeworm, is the pig. Taenia solium is a type of tapeworm that can live in the intestines of humans and pigs. Pigs become infected with the tapeworm when they ingest the eggs of the parasite, which can be present in contaminated food or water. Once inside the pig's digestive system, the tapeworm larvae hatch and penetrate the intestinal wall, then migrate to the pig's muscles and form cysts, which can be seen as small white spots in the meat. If a person eats undercooked pork that contains cysts of Taenia solium, they can become infected with the tapeworm. Once inside the human digestive system, the tapeworm can grow up to several meters long and attach itself to the intestinal wall, where it feeds on nutrients from the host's food. Therefore, it is essential to cook pork thoroughly and practice good hygiene to prevent infection with Taenia solium.

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The possession of scales, laying of eggs with shells, and bony structure of the head are characteristics shared by birds and reptiles. Scales are small, hard, and flattened structures that cover the skin of animals. Both birds and reptiles have scales, although they are modified differently in each group. For example, the scales of birds are found on their legs and feet, and they are made of keratin, which is the same material that makes up our hair and nails. In contrast, the scales of reptiles cover their entire body and are made of a variety of materials, including keratin and bone. Both birds and reptiles lay eggs with shells, which protect the developing embryo and provide a source of nutrients. The shells of bird eggs are hard and calcified, while those of reptile eggs can be hard or leathery, depending on the species. Finally, both birds and reptiles have a bony structure in their head called the skull. The skull protects the brain and provides a surface for muscle attachment. The skulls of birds and reptiles are both specialized for their respective lifestyles, with features such as a beak in birds and a long snout in many reptiles. So, in summary, the possession of scales, laying of eggs with shells, and bony structure of the head are characteristics shared by birds and reptiles.

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Although sodium ions are small, their charge prevents them from moving across the cell membrane through simple diffusion. They must be transported using active transport.

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Predation can reduce the population of a community. Predation refers to the act of one animal killing and eating another. When predators hunt and eat members of a particular population, it can cause a decrease in the number of individuals in that population. For example, a lion preying on a herd of zebras can reduce the number of zebras in the herd over time. When the number of individuals in a population decreases, it can also have a ripple effect on the entire ecosystem. For example, if the zebras in the above example are a primary food source for other predators, those predators may also experience a decrease in their population due to a lack of food. In conclusion, predation is a natural process that can cause a reduction in the population of a community, and it is an important factor in maintaining balance in the ecosystem.

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An enzyme is a protein that acts as a catalyst in biochemical reactions. Enzymes work by lowering the activation energy required for a reaction to occur. Activation energy is the minimum amount of energy needed to start a chemical reaction. By lowering the activation energy, enzymes make it easier for reactant molecules to form the necessary chemical bonds and undergo the reaction, leading to a faster reaction rate. This means that the correct answer is: "It lowers the activation energy of the reaction, increasing the reaction rate."

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An example of an organism that exists as a colony is Volvox. Volvox is a green alga that forms spherical colonies made up of hundreds to thousands of individual cells. The cells work together to perform functions such as movement and reproduction, giving the appearance of a single organism. However, each cell is still capable of functioning independently. This is an example of colonial organization, where individuals come together to form a larger entity that acts as a single organism.

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The appendicular skeleton is made up of the girdles and limbs. This means it includes the bones that form the pelvic girdle (the hip bones) and the shoulder girdle (the collarbone and shoulder blade) as well as the bones in the arms and legs. Basically, the appendicular skeleton is everything that is attached to the central part of the skeleton (the axial skeleton) and helps us move our limbs and make our movements more flexible and agile.

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Size, color, and fingerprints are examples of morphological variation. Morphological variation refers to differences in the physical appearance or structure of individuals within a species. This type of variation can be caused by genetic factors, environmental factors, or a combination of both. In the case of size, genetic factors can determine an individual's height or weight, while environmental factors such as nutrition can also play a role. Color variations can also be influenced by genetics as well as environmental factors such as diet or exposure to sunlight. Fingerprints, on the other hand, are determined by genetic factors and do not change throughout an individual's lifetime. Overall, morphological variation can be used to distinguish individuals within a species, and in some cases, can provide information about an individual's genetic makeup or environmental history.

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The feeding relationship among a set of members of a community is referred to as a "food chain." A food chain is a linear sequence of organisms where each member of the sequence is food for the next member. For example, a simple food chain could consist of grass as the producer, a grasshopper as the primary consumer, a bird as the secondary consumer, and a snake as the tertiary consumer. The grass is eaten by the grasshopper, which is then eaten by the bird, which is then eaten by the snake. A food web, on the other hand, is a more complex model that shows the interconnectedness of multiple food chains within an ecosystem. A pyramid of energy is a graphical representation of the amount of energy transferred between trophic levels in a food chain or food web, while a pyramid of members is not a commonly used term in ecology.