General Science Questions (MCQs) for Competitive Examinations

Notes:
Rhizobia are soil bacteria that fix nitrogen after becoming established inside root nodules of legumes. They are the only nitrogen-fixing bacteria living in a symbiotic relationship with legumes. Common crop and forage legumes are peas, beans, clover, and soy.

Notes:
Starfish carry out movements with the help of tube feet that are part of the water vascular system. Apart from their function in locomotion, the tube feet act as accessory gills. The water vascular system serves to transport oxygen from, and carbon dioxide to, the tube feet and also nutrients from the gut to the muscles involved in locomotion.

Notes:
Antibiotics are medicines used to treat a wide variety of infections or diseases caused by bacteria, such as respiratory tract infections (eg, pneumonia and whooping cough), urinary tract infections, skin infections and infected wounds. Antibiotics work by blocking vital processes in bacteria, killing the bacteria or stopping them from multiplying.

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Mostly medicinal herbs grown from 30 to 90 cm in height. They reach up to 30 cm in diameter.

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Bulbs are modified stems of some plants. The stem is modified to be a storage organ where the plant stores its reserve materials which it would use in times of need. It has a modified flower bud or other growth point that is surrounded by modified, fleshy leaves that are referred to as scales. Onion is the best example of bulb.

Notes:
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.

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Fructose, or fruit sugar, is a simple ketonic monosaccharide found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is a 6-carbon polyhydroxyketone with chemical formula of C6H12O6.

Notes:
Technically, the largest organ in the body is the liver. Liver is also the heaviest organ, with an average of 1.6 kilograms (3.5 pounds). The largest organ ‘of’ the body is the skin (the skin is ‘outside’ the body).

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As per the report of WWF the ten most endangered rivers emerge as: the Salween, La Plata, Danube, Rio Grande, Ganges, Murray-Darling, Indus, Nile, Yangtze and Mekong.

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Ornithophily refers to the pollination of flowering plants by birds. Birds involved in ornithophily tend to be specialist nectarivores with brushy tongues and long bills, that are either capable of hovering flight or light enough to perch on the flower structures.