General Science Questions (MCQs) for Competitive Examinations

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In biology, a pathogen or germ is anything that can produce disease. Typically, the term is used to describe an infectious agent such as a virus, bacterium, protozoa, prion, a fungus, or other microorganism. The scientific study of pathogens is called Pathology.

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Poliomyelitis, often called polio or infantile paralysis, is an infectious disease caused by the poliovirus. The virus is transmitted by person-to-person spread mainly through the faecal-oral route or, less frequently, by a common vehicle (e.g. contaminated water or food) and multiplies in the intestine, from where it can invade the nervous system and can cause paralysis.

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In human anatomy, the pleural cavity is the potential space between the two pleura (visceral and parietal) of the lungs. The pleura is a serous membrane which folds back onto itself to form a two-layered membrane structure. In pleural cavity of thorax lies three lobes of lungs on right side and two on the left hand side.

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Trachoma is a disease of the eye caused by infection with the bacterium Chlamydia trachomatis. It is the world’s leading cause of preventable blindness. According to the World Health Organization (WHO), trachoma is responsible for the visual impairment of 2.2 million people, of whom 1.2 million are irreversibly blind.

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The ozone layer refers to a region of Earth’s stratosphere that absorbs most of the Sun’s ultraviolet (UV) radiation. It absorbs 97–99% of the Sun’s medium frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface.

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Biofortification refers to the cultivation of crops to increase their nutritional value. The crops produced through biofortification method are always rich in nutrients like iron, zinc and Vitamin A. for example, Golden rice was produced using the method of biofortification. This rice is rich in beta-carotene and provides vitamin A to the children.

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Radon was once commonly used to treat cancer. The radiation it gives off kills cancer cells. However, the element must be used with great care because radiation can kill healthy cells as well. In fact, the bad side-effects of radiation therapy are caused by the killing of healthy cells by radiation. Today, radon is not as widely used for the treatment of cancer.

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Adrenalin is often referred to as ‘emergency hormones’ because they are released when a person feels excited. Thus, it is this hormone that often gives people the strength to do otherwise-impossible deeds and prevent emergencies.

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Depending on various geographical locations average air composition may change, but for the most part air, it is made up of 78% nitrogen (N2), 21% oxygen (O2), and trace amounts of carbon dioxide (CO2), methane (CH4), hydrogen (H2), argon (Ar) and helium (He). The CO2, CH4, H2, Ar, and He, when combined together, make up about 1% of our air.

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Coal worker’s pneumoconiosis, colloquially referred to as black lung disease, is a lung disease that results from breathing in dust from coal, graphite, or man-made carbon over a long period of time. Inhaled coal dust progressively builds up in the lungs and is unable to be removed by the body. This leads to inflammation, fibrosis, and in worse cases, necrosis of lungs.