General Science Questions (MCQs) for Competitive Examinations

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Decomposers recycle nutrients in the atmosphere. The nutrient cycle is a system where energy and matter are transferred between living organisms and non-living parts of the environment. This occurs as animals and plants consume nutrients found in the soil, and these nutrients are then released back into the environment via death and decomposition.

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Lymphatic system carries out the absorption of fats and fat-soluble vitamins from the digestive system and the subsequent transport of these substances to the venous circulation. Lymphatic vessels present in the intestinal villi absorb fatty acids and carries the digested food and fats from the small intestine. It acts as a reservoir of digested food and water.

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Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans as a source for tinder, medicine, food, and entheogens, as well as their dangers, such as poisoning or infection. From mycology arose the field of phytopathology, the study of plant diseases.

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The epidermis of the stem and the leaf is usually surrounded by a thin, covering called cuticle. It is formed by a waxy substance called cutin. It is meant for preventing excessive evaporation of water. Cuticle is absent in the root epidermis.

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Normal blood pressure is considered to be at or below 120 over 80 (120/80). Normally, blood pressures are usually categorized into three groups: low (90/60 or lower), high (140/90 or higher), and normal (values above 90/60 and below 130/80).

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The reason why bacteria does not grow in high concentration of sugar is because of sugar’s high osmotic and dehydrating effects. Sugar, in aqueous form, attempts to reach equilibrium with the sugar content of the food product with which it is in contact. This has the effect of drawing available water from within the food to the outside and inserting sugar molecules into the food interior. The result is a reduction of the so-called product water activity, a measure of unbound, free water molecules in the food that is necessary for microbial survival and growth. Sugar’s other antimicrobial mechanisms include interference with a microbe’s enzyme activity.

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Plague is caused by bacteria. It is a deadly infectious disease caused by the enterobacteria Yersinia pestis, named after the French-Swiss bacteriologist Alexander Yersin. It has led to death of million of people at one time.

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The richest sources of protein are animal foods such as chicken, meat, fish, cheese and eggs. However, plant proteins are believed to be healthier because of their lower fat content. Plant protein is found (e.g.) in beans (esp. soy beans), lentils, nuts, quorn and seeds. Fish and seafood are some of the richest sources of protein. Soybeans are legumes that provide a valuable protein-rich food option for vegetarians and non-vegetarians alike. One cup of boiled soybeans provides over 28g of protein.

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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.

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Sex determination in human beings depends on the particular pair of sex chromosomes an individual inherits. The homogametic sex, females, usually possess two identical sex chromosomes (XX). On the other hand, males, who are the heterogametic sex, typically present a pair of different sex chromosomes (XY). This distinct pair forms the blueprint that directs male physical and biological characteristics development.