JAMB UTME - Biology - 2015

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The cell is the basic unit of life, and there are two types of cells: plant cells and animal cells. Plant cells have some structures that animal cells do not have, such as cell walls and chloroplasts. However, there is one structure that is present in both plant and animal cells, and that is the cell membrane. The cell membrane is a thin, semi-permeable membrane that surrounds the cell, separating the cell's internal environment from the external environment. It is made up of a double layer of lipids and proteins, and it controls what goes in and out of the cell. In plant cells, the cell membrane is located inside the cell wall, which provides additional support and protection for the cell. In animal cells, the cell membrane is the outermost layer of the cell and is responsible for maintaining the cell's shape. Therefore, the correct answer is cell membrane, which is present in both plant and animal cells.

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Gaseous exchange refers to the exchange of oxygen and carbon dioxide between the blood and the air in the lungs. This process occurs in small sacs called alveoli, which are found in the lungs. When we inhale, air enters the lungs and travels through the trachea, then it divides into two bronchi and into smaller bronchioles. These bronchioles lead to clusters of alveoli, where the exchange of gases takes place. Oxygen from the inhaled air diffuses through the walls of the alveoli into the blood vessels, while carbon dioxide from the blood diffuses through the walls of the alveoli into the air in the lungs, which we then exhale out of our body. Thus, alveoli are the site of gaseous exchange in the lungs.

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A tissue is composed of a group of similar cells. These cells have the same structure and function, and they work together to perform a specific task within an organism. Examples of tissues include muscle tissue, which is composed of muscle cells that contract to produce movement, and nerve tissue, which is composed of nerve cells that transmit signals throughout the body. Tissues can combine to form organs, which in turn make up systems that work together to perform complex functions in the body.

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Influenza is not a sexually transmitted disease. Influenza, also known as the flu, is a highly contagious viral infection that primarily spreads through respiratory droplets when an infected person talks, coughs, or sneezes. It can also spread by touching a surface contaminated with the virus and then touching one's mouth, nose, or eyes. Unlike gonorrhea, herpes, and syphilis, which are sexually transmitted diseases, influenza is not typically spread through sexual contact. While some viruses can be transmitted through sexual activity, influenza is not one of them. To prevent the spread of influenza, it is important to practice good hygiene, such as washing your hands frequently, covering your mouth and nose when coughing or sneezing, and staying home when you are sick. Additionally, getting an annual flu vaccine is the most effective way to protect against influenza.

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Angiosperms belong to the class Spermatophyte. Angiosperms are flowering plants that produce seeds enclosed in an ovary (fruit). The class Spermatophyte includes all seed-bearing plants, both angiosperms and gymnosperms. Gymnosperms are a group of plants that produce seeds without an enclosing fruit, such as pine trees. Bryophytes and Pteridophytes are non-seed-bearing plants, while Thallophytes are a group of primitive, mostly unicellular or multicellular, plant-like organisms such as algae and fungi.

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The by-product of photosynthesis is oxygen (O2). Photosynthesis is the process by which plants, algae, and some bacteria convert carbon dioxide (CO2) and water (H2O) into glucose (C6H12O6) and oxygen (O2) using sunlight as a source of energy. During photosynthesis, light energy is absorbed by pigments called chlorophyll, which are located in the chloroplasts of plant cells. This energy is then used to split water molecules into oxygen gas and hydrogen ions. The oxygen gas is released into the atmosphere as a by-product of photosynthesis, while the hydrogen ions are used to create energy-rich molecules like ATP and NADPH, which are used to power the synthesis of glucose. In summary, the by-product of photosynthesis is oxygen (O2). During photosynthesis, plants and other photosynthetic organisms produce oxygen gas as a waste product, which is released into the atmosphere for other organisms to use in respiration.

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The primary consumer in the food chain below is the grasshopper. The food chain starts with green plants, which are producers, that produce their own food through photosynthesis. The grasshopper, which is an herbivore, eats the green plants, making it a primary consumer. The lizard is a secondary consumer that eats the grasshopper, while the snake is a tertiary consumer that feeds on the lizard. The hawk is at the top of the food chain and is known as the apex predator that preys on the snake. In a food chain, the primary consumer is the first organism that eats the producers. In this case, the grasshopper is the primary consumer because it feeds on the green plants, which are the producers in the food chain. The other organisms in the food chain, such as the lizard, snake, and hawk, are all consumers, but they occupy different levels in the food chain.

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Out of the options given, maize (corn) is not a monocotyledonous seed. A monocotyledonous seed, or a monocot seed, is a type of seed that only contains one embryonic leaf, called the cotyledon, in the seed. This is in contrast to dicotyledonous seeds, which have two embryonic leaves. Monocotyledonous seeds are found in plants that belong to the monocot group, which includes grasses, lilies, and orchids, among others. Cowpea, millet, and wheat are all examples of monocotyledonous seeds. Maize, on the other hand, is a dicotyledonous seed, and therefore not a monocotyledonous seed. It's important to note that the type of seed a plant produces can have implications for its growth and development, as well as its agricultural and economic value. Understanding the characteristics of different types of seeds is therefore important for farmers, scientists, and anyone interested in plant biology.

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The basic functional unit of the kidney is the nephron. The nephron is the basic functional unit of the kidney and is responsible for filtering the blood and removing waste products and excess fluid from the body. Each kidney contains about a million nephrons, which work together to perform the important functions of the kidney. The nephron is composed of several different parts, including the Bowman's capsule, the glomerulus, and the loop of Henle, which work together to filter the blood and produce urine. The Bowman's capsule surrounds the glomerulus, a network of tiny blood vessels, and acts as a filter to remove waste products and excess fluid from the bloodstream. The filtered fluid then flows through the loop of Henle, which helps to reabsorb important substances, such as glucose and electrolytes, and to regulate the concentration of the urine. The nephron is an incredibly complex and important structure, and its proper functioning is essential for maintaining the health and wellbeing of the body.

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In eukaryotic cells, cellular respiration takes place in the mitochondria. The mitochondria are specialized structures within eukaryotic cells that are responsible for generating energy for the cell. During cellular respiration, the mitochondria break down nutrients such as sugars and fats to release energy in the form of ATP (adenosine triphosphate). This process takes place within the inner membrane of the mitochondria. The nucleus is the control center of the cell and contains the cell's genetic material, while the cytoplasm is the gel-like substance that fills the cell and supports its organelles, and centrioles are structures involved in cell division.

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Volvox is a type of colony. A colony is a group of organisms that live together and work as a unit, like a tiny community. In the case of Volvox, it's a colony of green algae that live and move together in a spherical shape. Each individual alga is called a cell, and the cells work together to form a larger structure that can move as a whole. This helps the colony to survive and thrive in its environment.

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The emergency hormone in man is Adrenaline (also called epinephrine). Adrenaline is a hormone that is produced by the adrenal glands, which are located on top of the kidneys. It is released into the bloodstream when the body is under stress or when there is an emergency situation. Adrenaline increases the heart rate, boosts the supply of oxygen and glucose to the brain and muscles, and helps the body to respond to stress or danger. Adrenaline is sometimes referred to as the "fight or flight" hormone because it prepares the body to either fight or run away from a threat. For example, if a person is being chased by a predator, adrenaline will help them to run faster and be more alert. Adrenaline is also involved in the body's response to other stressful situations, such as public speaking or taking a test. In summary, adrenaline is an emergency hormone that helps the body to respond to stress and danger. It is produced by the adrenal glands and released into the bloodstream, where it prepares the body to either fight or flee from a threat.

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One of the diseases caused by fungi is coffee leaf rust. Coffee leaf rust is a fungal disease that affects coffee plants, causing leaves to turn yellow and fall off. The disease is caused by a fungus called Hemileia vastatrix, which infects the leaves of the coffee plant and reduces its ability to produce coffee beans. Cassava mosaic, leaf blight of cassava rosette, and groundnut disease, on the other hand, are caused by viruses and bacteria, not fungi. Cassava mosaic is caused by a virus, while leaf blight of cassava rosette is caused by bacteria. Groundnut disease is caused by a fungus, but it is not one of the options given in the question. In summary, coffee leaf rust is the disease caused by fungi among the options given. It is a fungal disease that affects coffee plants, while the other options are caused by viruses or bacteria.

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The vulva is not part of the mammalian male reproductive organ. The vulva is part of the female reproductive system, specifically the external genitalia. The epididymis, vas deferens, and testis, on the other hand, are all part of the mammalian male reproductive organ. The testis produces sperm and male sex hormones, while the epididymis and vas deferens are involved in transporting and storing sperm. In summary, the vulva is not part of the mammalian male reproductive organ. It is part of the female reproductive system, while the epididymis, vas deferens, and testis are all part of the male reproductive system.

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In the kidney, both useful substances and wastes are removed from the blood by filtration. The renal artery carries blood to the kidney, which then enters the nephrons where the blood is filtered. The process of filtration separates useful substances like water, glucose, amino acids, and minerals from wastes such as urea, uric acid, and creatinine. The useful substances are then reabsorbed into the blood while wastes are excreted through the renal tubules into the urine. Overall, filtration is a vital process for maintaining homeostasis in the body by keeping a balance between useful substances and waste products in the blood.

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The association between bacteria and root nodules of legumes is called mutualism. Mutualism is a type of symbiotic relationship in which both organisms involved benefit from the interaction. In this case, the bacteria (such as Rhizobia) take nitrogen from the air and convert it into a form that can be used by the plant, while the plant provides the bacteria with a source of energy in the form of carbohydrates. This allows the plant to grow better in nitrogen-poor soils and the bacteria to obtain nutrients from the plant. This type of mutualistic relationship is important in agriculture, as legumes are often used as a crop to naturally enrich soil with nitrogen.

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The breaking down of food in the alimentary canal is called digestion. Digestion is the process of breaking down food into simpler substances that can be absorbed and used by the body. It involves both mechanical and chemical processes. The mechanical process involves the physical breakdown of food into smaller pieces, which increases the surface area for chemical digestion. Chemical digestion, on the other hand, involves the breakdown of large molecules such as proteins, carbohydrates and fats into smaller molecules such as amino acids, glucose, and fatty acids. These smaller molecules can be absorbed into the bloodstream and transported to the cells for energy and other functions. Therefore, the correct answer is "digestion".

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Auxins is not a waste product of plants. Auxins are a type of plant hormone that regulates various aspects of plant growth and development, such as stem elongation, root growth, and tropisms (movement in response to stimuli like light or gravity). On the other hand, gum, resins, and tannins are all waste products of plants. Gum is a sticky substance that is produced by some plants as a way to seal wounds or protect themselves from pathogens. Resins are produced by many types of trees as a way to protect themselves from insects and other pests, and also to seal wounds. Tannins are a type of chemical compound that is produced by plants as a defense against herbivores, and can also be used to help protect the plant from fungal and bacterial infections. So in summary, auxins are not a waste product of plants but rather an important plant hormone that plays a key role in regulating various aspects of plant growth and development.

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The part that is not involved in the breathing process is the mouth. The breathing process involves inhaling air through the nostrils, which passes through the nasal cavity, and then enters the lungs. During inhalation, the ribs and the diaphragm expand to create more space for the lungs to fill with air. Then, during exhalation, the ribs and the diaphragm relax and contract to push the air out of the lungs. Therefore, the correct answer is "mouth".

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The correct option is "Excretion of CO2." The kidneys are a pair of bean-shaped organs that are located in the abdomen. They are responsible for several important functions in the body, including regulation of water content, maintenance of blood pH and homeostasis, and removal of waste products from the blood. However, the excretion of CO2 is primarily carried out by the lungs through the process of respiration. The kidneys do play a role in maintaining acid-base balance in the body, but this is not related to the excretion of CO2.

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Invertebrates are animals that do not have a backbone or spinal column. They make up the vast majority of the animal kingdom, with about 97% of all animal species being invertebrates. One of the options listed is not an invertebrate, and that is "chordate." Chordates are a group of animals that have a notochord, which is a flexible rod-like structure that runs along the length of their body. They also have a dorsal nerve cord and pharyngeal gill slits at some point in their life cycle. Examples of chordates include fish, birds, mammals, and reptiles. The other options listed are all invertebrates. Flatworms and roundworms are both types of worms that do not have a backbone. Protozoans are single-celled organisms that do not have a backbone or any other type of skeletal structure. Therefore, the correct answer is "chordate," which is not an invertebrate because it has a notochord and other characteristics that are not found in invertebrates. The other options listed are all invertebrates because they do not have a backbone or spinal column.

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The organ that removes the largest amount of excess water from the body is the kidney. The kidney is responsible for regulating the water content in the blood by filtering waste products and excess water from the blood, which is then excreted in the form of urine. The kidneys are able to filter and remove large amounts of excess water, which helps to maintain the body's fluid balance and prevent dehydration. While the liver, lungs, and skin all play important roles in maintaining the body's overall health, they do not remove as much excess water from the body as the kidneys do.

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The correct answer is "rickets." Vitamin D is essential for the body to absorb calcium, which is needed for the development and maintenance of strong bones. Without enough vitamin D, bones become soft and weak, a condition known as rickets in children and osteomalacia in adults. Rickets can lead to bone pain, muscle weakness, and an increased risk of fractures. In severe cases, it can cause deformities of the skeleton, such as bowed legs or an abnormal curvature of the spine. Vitamin D deficiency can also increase the risk of developing osteoporosis, a condition in which bones become fragile and are more likely to break. Vitamin D is often called the "sunshine vitamin" because the body can produce it when the skin is exposed to sunlight. However, it can also be obtained from certain foods, such as fatty fish, egg yolks, and fortified milk and cereals. In some cases, vitamin D supplements may be needed to ensure adequate intake.

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Out of the options given, viruses cause Ebola fever. Ebola fever, also known as Ebola virus disease, is a severe and often fatal illness caused by the Ebola virus. The virus is a member of the family Filoviridae, which also includes the Marburg virus. The Ebola virus was first identified in 1976 during an outbreak in Sudan and the Democratic Republic of Congo, and since then, there have been several outbreaks in various parts of Africa. The Ebola virus is highly contagious and is spread through contact with bodily fluids of infected people or animals. The virus can cause a range of symptoms, including fever, fatigue, muscle pain, headache, and sore throat, among others. In severe cases, it can lead to bleeding and organ failure. While there is currently no specific treatment for Ebola fever, supportive care can help improve the chances of survival. Prevention efforts include strict infection control practices in healthcare settings, safe burial practices for those who have died from the disease, and community education and engagement. In summary, viruses cause Ebola fever, not bacteria, fungi, or protozoa.

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The hormonal gland that is located on top of the kidney is called the adrenal gland. The adrenal glands are a pair of small, triangular-shaped glands that sit on top of each kidney. They are responsible for producing and secreting hormones that are essential to the body's normal functioning, including cortisol, adrenaline, and aldosterone. These hormones help regulate a wide range of bodily processes, including the stress response, blood sugar levels, blood pressure, and electrolyte balance. In summary, the adrenal gland is a critical hormonal gland located on top of each kidney that helps regulate the body's many processes.

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Sneezing is not voluntarily controlled by the brain. Sneezing is a reflex that is triggered by various stimuli, such as dust, bright light, or a strong odor. The brain does not have direct control over the sneezing reflex, which is instead controlled by the autonomic nervous system. The autonomic nervous system is responsible for controlling many unconscious bodily functions, such as breathing, heart rate, and digestion, and does not respond to voluntary control. When a person sneezes, the muscles in the nose and chest contract rapidly, expelling air and any irritants that may be present in the nasal passages. While a person may be able to suppress a sneeze temporarily, they cannot prevent it from happening entirely.

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The correct answer to the question is the "skull." The skull is a bony structure that encloses and protects the brain in humans. It is a part of the human body's skeletal system and forms the upper part of the head. The brain is the control center of the human body and is responsible for many functions, including movement, sensation, thought, and consciousness. The skull protects the brain from injury, shock, and trauma, and is a vital part of the human body's protective mechanisms. The spinal column, or vertebral column, is a series of bones that protect the spinal cord and allows movement and flexibility, but it is not the main protective structure for the brain.

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The gland that releases hormones into the blood is part of the endocrine system. The endocrine system is a complex network of glands and organs that produce, store, and release hormones into the bloodstream. Hormones are chemical messengers that help to regulate a wide range of bodily functions, such as growth and development, metabolism, and reproductive processes. The glands of the endocrine system include the pituitary gland, thyroid gland, adrenal glands, pancreas, and reproductive glands (ovaries and testes). Each gland produces different hormones that travel through the bloodstream to target cells and organs throughout the body. When a hormone reaches its target cell, it binds to a specific receptor on the surface of the cell, triggering a series of chemical reactions that ultimately lead to a specific response. For example, the hormone insulin, which is produced by the pancreas, helps to regulate blood sugar levels by signaling cells to take up glucose from the bloodstream. In summary, the glands that release hormones into the blood are part of the endocrine system. This system is responsible for producing and releasing hormones that regulate various bodily functions and help to maintain homeostasis (a stable internal environment) in the body.

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Cone cells, or cones, are one of two types of photo-receptor cells in the retina of the eye. They are responsible for color vision and function best in relatively bright light, as opposed to rod cells, which work better in dim light. Cone cells are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones which quickly reduce in number towards the periphery of the retina. There are about six to seven million cones in a human eye and are most concentrated towards the macula

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Earthworms are invertebrate animals that play an important role in soil ecology. They have a closed circulatory system, a simple nervous system, and a segmented body with many specialized structures. One of the structures used for excretion in earthworms is called the nephridium. The nephridium is a tubular structure found in each body segment of an earthworm. It functions as the excretory organ of the earthworm and is responsible for filtering waste products from the blood and removing them from the body. The nephridium is similar in function to the kidneys of mammals. The process of excretion in earthworms begins with the coelomic fluid, which is a fluid that fills the body cavity of the earthworm. The nephridium filters the coelomic fluid, removing waste products such as nitrogenous compounds and excess water. The waste products are then transported to the outside of the body through small openings called nephridiopores. In contrast, the other structures listed in the options are not used for excretion in earthworms. The contractile vacuole is used by some aquatic organisms to expel excess water from the body, the flame cell is used by some flatworms for excretion, and the Malpighian tubule is used by some insects to remove waste products from the body. Therefore, the correct answer is nephridium, which is used for excretion in earthworms.

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The theory of survival of the fittest was propounded by Charles Darwin. This theory, also known as natural selection, suggests that organisms that are best adapted to their environment are more likely to survive and reproduce than those that are less well adapted. Over time, the traits that contribute to survival and reproduction become more common in the population, leading to evolution. Darwin's theory of evolution through natural selection is one of the most important and influential scientific theories in history.

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Fish are aquatic animals that come in many different shapes, sizes, and colors. They have unique characteristics that help them survive and thrive in their watery environments. However, there is one statement among the options given that is not true of a fish, and that is "they are homeothermic." Homeothermic animals, also known as warm-blooded animals, have the ability to maintain a constant body temperature regardless of changes in the external environment. This ability allows them to live in a wide range of environments, from cold polar regions to hot deserts. Examples of homeothermic animals include mammals and birds. In contrast, fish are not homeothermic. They are poikilothermic animals, also known as cold-blooded animals, which means that their body temperature is determined by the temperature of their surroundings. They cannot regulate their body temperature internally like warm-blooded animals can. Instead, they rely on their behavior, such as moving to different water depths or areas, to maintain their preferred body temperature. Therefore, the correct answer is "they are homeothermic," which is not true of a fish. Fish respire with the use of gills, are covered with scales, and are poikilothermic animals.

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Spirogyra is not a free-living organism. It is a type of algae that lives in freshwater environments and forms long, spiral-shaped filaments. The other three options, Amoeba, Chlamydomonas, and Euglena, are all single-celled organisms that are capable of surviving and reproducing on their own, without being attached to a larger organism.

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The lowest unit of classification is the species. In biology, species is the basic unit of classification and the most specific level of classification in the hierarchical classification system. A species is defined as a group of living organisms that are capable of interbreeding and producing fertile offspring. This means that members of the same species can mate and have babies that can also reproduce. The species is the smallest unit of classification in the biological system, and all living organisms can be classified into a species based on their shared characteristics and genetic makeup. Above the species level, organisms are classified into higher levels such as genus, family, order, class, phylum, kingdom, and domain, based on their similarities and evolutionary relationships. These higher levels of classification group species into larger and more inclusive categories, allowing us to understand the relationships between different types of organisms and the diversity of life on Earth.

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The part of the cell responsible for the production of energy is the mitochondrion. The mitochondria are often referred to as the "powerhouses" of the cell because they produce the energy that the cell needs to function. They do this by breaking down sugars and other molecules in a process called cellular respiration. This process releases energy that the cell can use, and the mitochondria are where this process takes place. The nucleus is the control center of the cell and contains the cell's genetic material, while the cytoplasm is the gel-like substance that fills the cell and supports its organelles, and the cell membrane is a thin, flexible barrier that surrounds the cell and controls what enters and exits it.

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An oviparous animal is an animal that lays eggs, and the eggs hatch outside the mother's body. Among the options given, the only example of a non-oviparous animal is the rat. Rats are viviparous animals, which means that their offspring develop inside the mother's body and are born alive. On the other hand, crocodiles, doves, and tilapia are all oviparous animals. Crocodiles lay eggs on land, and the mother guards the eggs until they hatch. Doves lay eggs in nests and incubate them until the chicks hatch. Tilapia, a type of fish, lay eggs in nests, and the males protect the eggs until they hatch. In summary, among the options given, only the rat is not an oviparous animal because it gives birth to live offspring.

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Hormones that help regulate blood calcium levels are produced by the parathyroid. The parathyroid glands are small glands located in the neck near the thyroid gland. They produce a hormone called parathyroid hormone (PTH), which helps to regulate the levels of calcium in the blood. PTH works by increasing the release of calcium from the bones into the bloodstream, and by decreasing the amount of calcium that is lost in the urine. This helps to maintain a stable level of calcium in the blood, which is essential for many important physiological processes, such as muscle contraction, nerve function, and blood clotting. In addition to PTH, the kidneys and the intestines also play a role in regulating blood calcium levels by controlling the amount of calcium that is absorbed from the diet and the amount that is excreted in the urine. Together, these different hormones and organs work to keep the levels of calcium in the blood within a narrow and healthy range.

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The scientific study of life is biology. Biology is the branch of science that deals with the study of living organisms and their interactions with the environment. This includes the study of everything from the smallest microorganisms to the largest animals and plants. Biologists use a variety of scientific methods and techniques to study life, including observation, experimentation, and data analysis. Some of the major fields of biology include botany (the study of plants), zoology (the study of animals), and ecology (the study of the interactions between living organisms and their environment).

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The population of different organisms that exist together in a habitat is called a "community." In ecology, a community is defined as a group of different species that live and interact with each other in a particular habitat. This means that within a community, there are many different kinds of organisms, such as plants, animals, and fungi, that all depend on each other in various ways. For example, in a forest community, there may be trees, birds, insects, and small mammals that all interact with each other through processes like predation, competition, and mutualism. Each species plays a unique role in the community, and the community as a whole is shaped by the interactions between these different species. Understanding communities is an important part of ecology because it helps us to understand how different species interact with each other and with their environment. By studying communities, scientists can learn more about the complex web of relationships that exists between different organisms, and how these relationships contribute to the overall health and functioning of ecosystems.

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Viviparous animals are those that give birth to live young, as opposed to laying eggs. Out of the animals listed, the pigeon is the only oviparous (egg-laying) animal. The cow, dog, and goat are all viviparous, giving birth to live young.

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The correct answer is "isotonic." When the concentration of solutes in the cell and the surrounding medium is the same, the solution is said to be isotonic. In an isotonic solution, there is no net movement of water across the cell membrane, and the cell maintains its shape and size. On the other hand, in a hypertonic solution, the concentration of solutes is higher outside the cell, causing water to move out of the cell and leading to shrinkage or crenation of the cell. In a hypotonic solution, the concentration of solutes is lower outside the cell, causing water to move into the cell and leading to swelling or lysis of the cell. Maintaining the proper concentration of solutes inside and outside of cells is important for the proper functioning of living organisms. Cells use various mechanisms to regulate the movement of water and solutes across their membranes to maintain isotonic conditions when necessary.

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The translucency spot in a food test shows the presence of fats. This is because fats are translucent and tend to show up as clear spots on a piece of paper or cloth used for a food test. The test involves placing a small amount of the food on a piece of paper or cloth and observing any changes or spots that appear. If a translucent spot appears, it indicates the presence of fats in the food sample. This is a simple and quick test that can be used to determine the presence of fats in various types of food.

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