Biology MCQs

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Green Revolution related to Agriculture. It took place between 1950-1960 and focused mainly on increasing agricultural production and started in Mexico.

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The recognition site is the sequence of DNA where the DNA is cleaved. The presence of more than one recognition site can result in multiple cuts within the DNA leading to DNA fragmentation. This would complicate the process of gene cloning.

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Keratin is a family of fibrous structural proteins that is the key structural component of hair and nails. It is also the key structural material making up the outer layer of human skin. Besides, it provides the necessary strength and toughness for masticatory organs, such as the tongue.

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A thick vein seen in the middle of the leaf is called the midrib. Pinnately veined leaves have one large central vein, called the midrib, which extends from the base of the blade to its tip. Other large veins branch off on each side of the midrib. The leaves of beech, birch, and elm trees have such a vein pattern.

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Calyptrogen is a layer of rapidly dividing cells at the tip of a plant root, from which the root cap is formed. It occurs in grasses and many other plants. The root cap is formed by several layers of cells that envelop the root tip externally. This covering of cells, of which the outermost ones are dead, envelops and protects the growing tip of root.

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The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening. Guard cells are specialized cells in the epidermis of leaves, stems and other organs that are used to control gaseous exchange and rate of transpiration.

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Based on the dividing capacity of the tissues, various plant tissues can be classified as growing or meristematic tissue and permanent tissue. Meristem is a type of tissue system in plants, composed of a mass of undifferentiated cells and their primary function is to take part in the growth of plants. Permanent tissues are differentiated tissues doing specific functions such as conduction, providing mechanical support or carrying out photosynthesis etc.

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The term fish is most strictly used to describe any animal with a backbone that has gills throughout life and has limbs, if any, in the shape of fins. Many types of aquatic animals commonly referred to as fish are not fish in this strict sense; examples include shellfish, cuttlefish, starfish, crayfish and jellyfish.

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The Eustachian Tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. It help to maintain air pressure of body with respect to atmospheric air pressure. It’s also because of this people flying by air feel pain in their ears when flying for long hours together.

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Bicuspid valve is located between the left atrium and left ventricle. The mitral valve is also called the bicuspid valve because it contains two leaflets or cusps. It is on the left side of the heart and allows the blood to flow from the left atrium into the left ventricle.