Biology MCQs

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The human brain is the central organ of the human nervous system, and with the spinal cord makes up the central nervous system. It is considered to have the Least generative power.

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Cuttlefish or cuttles are marine molluscs of the order Sepiida. related to the octopus and squid and characterized by a thick internal calcified shell called the cuttlebone.

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Meningitis is a disease which is characterized by inflammation of meninges, the covering that lie over the brain and spinal chord is caused by bacteria. The meninges are the three membranes that cover the brain and spinal cord.

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Theory of natural selection was proposed by Darwin.The theory is an explanation for adaptation and speciation. He defined natural selection as the “principle by which each slight variation [of a trait], if useful, is preserved”.

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The cork cells are impervious to water. Suberin is responsible to give this quality to Cork. Suberin, cutin and lignins are complex, higher plant epidermis and periderm cell-wall macromolecules, forming a protective barrier.

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Cone cells and Cone cells are one of three types of photoreceptor 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.

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Peepal tree has the capability to absorb CO² at night due to Crassulacean Acid Metabolism (CAM). It’s a photosynthesis pathway primarily found in desert plants and epiphytes (those that live on larger trees). During the day, CAM plants break down the malate created at night and use the released CO² to create sugars, similar to C3 plants. But, CAM, being energy inefficient, is used only under certain conditions. It seems that peepal trees use CAM when they are epiphytic and switch to C3 photosynthesis when they settle in the soil.

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The beak, bill or rostrum is an external anatomical structure of birds that is used for eating and for preening, manipulating objects, killing prey, fighting, probing for food, etc. All beaks are composed of two jaws, generally known as the upper mandible (or maxilla) and lower mandible (or mandible).

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Rhizobium is a kind of symbiotic bacteria. Many legumes have root nodules that provide a home for symbiotic nitrogen-fixing bacteria called rhizobia. This relationship is particularly common in nitrogen-limited conditions. The Rhizobia convert nitrogen gas from the atmosphere into ammonia.

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In biology, tissue is a cellular organizational level between cells and a complete organ. Animal tissues are grouped into four basic types: connective, muscle, nervous, and epithelial.