General Science Questions (MCQs) for Competitive Examinations

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Chemical weapons are called “poorman’s bomb”. These cause catastrophic damage, and are easy to produce. Sarin is a colorless and odourless agent, and is extremely potent. It was used in Damascus in 2013. Mustard Gas is possibly the most commonly used chemical agent and gets its name from the distinctive odour of rotten mustard. It is less potent and usually only 5 to 10 percent people exposed to it usually die. It was widely used during Second World War. VX is a nerve agent which is odourless and appears as brownish oily substance.

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Holstein Friesian cows are world’s highest-production dairy animals and dominate the global dairy industry. These cows originated in Dutch provinces of North Holland and Friesland, and Schleswig-Holstein in Northern Germany. They are known as Holsteins in North America and Friesians in UK and Ireland.

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Ecological succession is unidirectional progressive process of development in an ecosystem or biome. Grass ecosystems are an early stage of succession in regions where the mature ecosystems are forests. However, grass ecosystems are climax ecosystems in grassland regions, where there is not enough rainfall to support a forest. Due to limiting factors such as water scarcity and forest fire, a grassland ecosystem changes to a desert ecosystem. The ecological succession of grassland is desert.

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Plant wilting occurs after excessive loss of water by transpiration and lesser absorption. i.e. rate of transpiration exceeds rate of water absorption. On a hot day, plants transpire heavily and cannot absorb water speedily to keep pace with transpiration loss, even when there is enough water.

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Barani area are traditionally rain-fed areas. These are any low rain area where the rain-fed dry farming is practiced. Bagar tract, the dry sandy tract of land on the border of Rajasthan state adjoining the states of Haryana and Punjab, is an example of Barani land.

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Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamine – epinephrine) to accelerate the heart rate. The parasympathetic nervous system (PNS) releases the hormone acetylcholine to slow the heart rate.

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Photosynthesis is the process by which light energy is converted into chemical energy by organisms. Carbon dioxide and water are the raw materials of this process. The light energy comes from the Sun and its end products are oxygen and glucose.

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Riboflavin, also known as vitamin B2 is an easily absorbed colored micronutrient with a key role in energy metabolism, and for the metabolism of fats, ketone bodies, carbohydrates, and proteins.

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Plants and photosynthetic organisms utilize this solar energy in fixing large amounts of CO2 while amounts consumed by human beings are relatively small representing only 10% of the energy converted during photosynthesis. The process of photosynthesis in plants involves a series of steps and reactions that use solar energy, water, and carbon dioxide to produce organic compounds and oxygen.

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Yeasts, moulds (molds), and mushrooms are examples of fungi. Mushrooms are another group of fungi, which are mainly Basidiomycetes and partially Ascomycetes, both of which share a same feature — having a macroscopic “Fruiting-body, a Mushroom”. Yeasts are eukaryotic, single-celled micro organisms classified as members of the fungus kingdom.