Biology MCQs

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Infection can occur when a healthy person inhales droplets from the saliva, sputum, or nasal passages of an infected person.

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A plasmid is an autonomously repeating circular extra-chromosomal DNA. They naturally exist in bacterial cells, and they also occur in some eukaryotes.

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The first transgenic crop was Tobacco (a virus-resistance plant), which was developed in the year 1983.

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A heart attack occurs when blood flow to a part of your heart is blocked for a long enough time that part of the heart muscle is damaged or dies. The medical term for this is myocardial infarction. Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. If the blood flow is blocked, the heart is starved of oxygen and heart cells die.

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Pond silk is the common name of Spirogyra (algae) because it is very slimy in shape. It is also known as pond silk, water silk, pond scum or mermaid’s trees because of its bright green silky appearance. Its filaments shine like silk due to the presence of mucilage and spiral shaped chloroplast.

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Tuberculosis caused by Mycobacterium tuberculie which primarily affects lungs although can affect other body too while early 19th century was called ‘white plague’ because of the large number of the people dying of its infection.

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Conduction is the process by which vital nutrients are transported to the different parts of a plant. This process is independent of the light factor. Respiration process in plants is the intake of carbon-dioxide and exhales oxygen during the day as the plants gets energy through the photosynthesis process in which the carbon-dioxide is converted into sugars using the sun light energy, as this process uses carbon-dioxide and water, the resulting gas oxygen is given out as a waste product. During the night, as the photosynthesis process does not take place it exhales the carbon-dioxide itself.

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When freshwater fish is placed in salt water, the water molecules contained in the fish’s body would pass through the cell membranes of the fish, causing the fish to lose water by osmosis. This sudden change in the molecular makeup of the fish would cause the fish to undergo severe dehydration followed by death.

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Arrector pili is a microscopic band of muscle tissue which connects a hair follicle to the dermis. ? When stimulated, the arrector pili will contract and cause the hair to become more perpendicular to the skin surface (stand on end), known colloquially as goose bumps.

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Sea hares are molluscs. They belong to Phylum Mollusca and Class Gastropoda like snails. Like many other sea slugs (Subclass Opistobranchia), sea hares lack external shells as adults. Sea hares belong to Order Anaspidea.