General Science Questions (MCQs) for Competitive Examinations

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R.H. Whittaker (1969) proposed a Five Kingdom Classification: Monera, Protista, Fungi, Plantae and Animalia. The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.

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Most of Earth’s oxygen comes from tiny ocean plants – called phytoplankton – that live near the water’s surface and drift with the currents. Like all plants, they photosynthesize – that is, they use sunlight and carbon dioxide to make food. Scientists believe that phytoplankton contribute between 50 to 85 percent of the oxygen in Earth’s atmosphere (National Geographic).

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Those who eat a well-balanced diet and have no metabolic disorders, excess dietary carbohydrates?are converted by the liver into complex chains of glucose called glycogen. Glycogen is stored in liver and muscle cells and is a secondary source of energy to freely circulating blood glucose.

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The Widal test is used to help make a presumptive diagnosis of enteric fever, also known as typhoid fever. Typhid is the other test used to ascertain the diagnosis of typhoid fever.

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Cellular respiration takes place in the mitochondria. Cellular respiration allows for the release of energy stored in chemical bonds of glucose (obtained from food) to form adenosine triphosphate, which is the energy currency of the cell. For every molecule of glucose, 36 molecules of ATP are made.

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Most of the transpiration occurs through foliar surface or surface of the leaves. It is known as foliar transpiration. Foliar transpiration accounts for over 90% of the total transpiration. The rest is mostly lenticular that occurs through holes in bark called lenticels.

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Both male and female mosquitoes eat the same things—nectar, plant sap, or honeydew (a sticky substance excreted by aphids)—for energy. But only female mosquitoes imbibe a blood meal. The females need the protein in blood platelets to develop eggs. Male mosquitoes don’t have specific mouthparts to pierce skin and access blood vessels.

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A vector-borne disease is one in which the pathogenic microorganism is transmitted from an infected individual to healthy individual by an arthropod or other agent, sometimes with other animals serving as intermediary hosts. The transmission depends upon the attributes and requirements of at least three different living organisms: the pathogenic agent, either a virus, protozoa, bacteria, or helminth (worm); the vector, which are commonly arthropods such as ticks or mosquitoes; and the human host.

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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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Femur (thigh bone) is the longest bone in the human body. It is the upper bone of the leg or hind leg. The head forms a ball-and-socket joint with the hip, being held in place by a ligament within the socket and by strong surrounding ligaments. By most measures the femur is the strongest bone in the body.