General Science Questions (MCQs) for Competitive Examinations

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Tears are a clear liquid secreted by the lacrimal glands (tear ducts) in the eyes of all land mammals. The lacrimal glands are situated in the upper lateral region of each orbit, in the lacrimal fossa of the orbit formed by the frontal bone. They are paired, almond-shaped exocrine glands, one for each eye.

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Three common sugars (glucose, galactose and fructose) share the same molecular formula: C6H12O6. Because of their six carbon atoms, each is a hexose. They are “single” sugars or monosaccharides.

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Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent hypocalcemic tetany. It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts. Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults.

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Keratin is a family of fibrous structural proteins that is the key structural material making up hair, horns, claws, hooves, and the outer layer of human skin. Keratin is also the protein that protects epithelial cells from damage or stress. Some keratins have also been found to regulate key cellular activities, such as cell growth and protein synthesis.

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Triploblasty is a condition of the blastula in which there are three primary germ layers: the ectoderm, mesoderm, and endoderm. The germ layers form during gastrulation of the blastula. All “higher” and “intermediate animals” (from flat worms to humans), arise from a triploblastic ovum. Triploblastic organisms generally possess bilateral symmetry.

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Binomial nomenclature is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms. The formal introduction of this system of naming species is credited to Swedish natural scientist Carlous Linnaeus, effectively beginning with his work ‘Species Plantarum’ in 1753 followed by “Systema” Nature.

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Edward Jenner introduced the vaccine for smallpox. Smallpox was an infectious disease caused by one of two virus variants, Variola major and Variola minor. In 1980, the World Health Organization declared smallpox an eliminated disease.

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Down syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is typically associated with physical growth delays, characteristic facial features and mild to moderate intellectual disability.

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The Passenger Pigeon or Wild Pigeon is an extinct North American bird. The species lived in enormous migratory flocks until the early 20th century, when continued hunting and habitat destruction led to its demise.

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Robert Harding Whittaker was a distinguished American plant ecologist who was the first to pro pose the five-kingdom taxonomic classification of the world’s biota into the Animalia, Plantae, Fungi, Protista, and Monera in 1969. He also proposed the Whittaker Biome Classification, which categorized biome-types upon two abiotic factors: temperature and precipitation.