General Science Questions (MCQs) for Competitive Examinations

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Compound eyes are found among the arthropods and are composed of many simple eye sets called ommatids. These may give either a single pixelated image or multiple images, per eye. Each sensor has its own lens and photosensitive cells. Some eyes have up to 28,000 such sensors, which are arranged hexagonally give a full 360° field of vision. Compound eyes are very sensitive to motion. With each eye viewing a different thing, a fused image from all the eyes is produced in the brain, providing very different, high resolution images.

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Polycythemia is an abnormally high concentration of haemoglobin in the blood through an increase in red cell numbers. People with this condition have thicker blood, which makes it harder for blood to circulate around the body. A relatively stable number of RBCs is maintained in the circulation by increasing or decreasing the rate of production by the bone marrow.

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Platelets, also called thrombocytes, are a component of blood whose function is to stop bleeding by clumping and clotting blood vessel injuries. Unlike red and white blood cells, platelets are not actually cells but rather small fragments of cells.

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Ornithology is a branch of zoology that deals with the study of birds. The science of ornithology has developed several key concepts in evolution, behaviour and ecology such as the definition of species, the process of speciation, instinct, learning, ecological niches, guilds, island biogeography, phylogeography and conservation.

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Bariatric surgical procedures cause weight loss by restricting the amount of food the stomach can hold, causing malabsorption of nutrients, or by a combination of both gastric restriction and malabsorption. The most common bariatric surgery procedures are gastric bypass, sleeve gastrectomy, adjustable gastric band, and biliopancreatic diversion with duodenal switch. Gastric bypass and other weight-loss surgeries make changes to digestive system.

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Interbreeding destroys the genetic integrity of a species, causing it to become progressively infertile or extinct, evolutionary changes in anatomy and biology developed to prevent interbreeding between species. The specific term is Reproductive Isolation, which acts to prevent some, any, or all stages of reproduction from occurring. Reproductive Isolation is very important in keeping animal species separated.

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A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The pulmonary arteries are unique in that unlike most arteries which carry oxygenated blood to other parts of the body, the pulmonary arteries carry de-oxygenated blood to the lungs. After picking up oxygen, the oxygen rich blood is returned to the heart via the pulmonary veins.

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In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure. In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. The chromosome holds not only the genetic code, but many of the proteins responsible for helping express it.

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Mostly medicinal herbs grown from 30 to 90 cm in height. They reach up to 30 cm in diameter.

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An insect is an organism having three pairs of jointed legs. Insects are small, land-dwelling arthropods. It has three distinct body sections : the head, thorax and abdomen. It has one pair of antennae (comprising the scapele, pedicel and flagellum), compound eyes and often one or two pairs of wings.