General Science Questions (MCQs) for Competitive Examinations

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In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged.

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Lysosomes are called the suicide bags of the cells they contain digestive enzymes, and break down food, cellular debris and foreign invaders like bacteria. When the cell is injured beyond repair, or becomes old, the lysosome digests the cell. So, it is called “suicide bag of the cell.”

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Multicellular organisms are made up of more than one cell. The development of multicellular organisms is accompanied by cellular specialization and division of labor; cells become efficient in one process and are dependent upon other cells for the necessities of life. Paramecium is single-celled protists naturally found in aquatic habitats. Paramecium is the only genus in the family Parameciidae, which resides within the phylum Ciliophora.

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Land snails, insects, birds, and some reptiles excrete uric acid as the major nitrogenous waste. The white, crystalline substance seen in a typical bird or lizard “poop” is actually urine: a little pool of uric acid crystals in a very small amount of water.

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The Taungya system involves growing agricultural crops between rows of planted trees (sal, teak, etc). Along with jhum cultivation, it is one of the well-known systems of agro forestry programmes in practice in our country.

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The best way of getting rid of non-biodegradable waste such as plastic is by recycling them. Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. Recycling is a key component of modern waste reduction and is the third component of the “Reduce, Reuse, and Recycle” waste hierarchy. Burning may release toxic gas into the atmosphere. Burying and dumping will hardly solve anything because of their very long life of self decomposition.

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Swedish naturalist Carlous Linnaeus established the binomial system of naming living organisms, setting a format and a structured process for classifying the interrelationships between plants (among which he included all fungi), and between animals. The binomial system that Linnaeus devised enables an author to refer to a species confident that it will mean the same thing to informed readers anywhere else in the world.

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Sharks possess a heterocercal caudal fin in which the dorsal portion is usually noticeably larger than the ventral portion. This is because the shark’s vertebral column extends into the dorsal portion, providing a greater surface area for muscle attachment.

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An isogenic graft or Isograft is a graft between genetically identical individuals (i.e. monozygotic twins). This type of graft donot pose any form of tissue rejection threat by recipient’s body.

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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.