General Science Questions (MCQs) for Competitive Examinations

Notes:
The melting point of a pure substance is always higher than the melting point of that substance when a small amount of an impurity is present. Melting point decreases with increase of impurity in water. Increase in impurity increases the electrostatic attraction between ions and thus more energy is needed to break the bonds. The surface tension of water increases when highly soluble impurities are added to it.

Notes:
Enzymes are defined as biological catalysts. Chemically all enzymes are globular proteins. Each enzyme catalyses only one chemical reaction. Protein part of enzyme is known as Apoenzyme. It forms an active enzyme system by combination with a coenzyme and determines the specificity of this system for a substrate.

Notes:
When a plant is placed under the fan, the speed of air is increased which leads to high rate of transpiration through the stomata. The increase in the rate of transpiration increases the water absorption also. As by keeping the plants under the fan, the transpiration process is boosted. Therefore, more amount of water and other minerals are absorbed by the plant roots from the soil.

Notes:
Conduction is the process by which vital nutrients are transported to the different parts of a plant. This process is independent of the light factor. Respiration process in plants is the intake of carbon-dioxide and exhales oxygen during the day as the plants gets energy through the photosynthesis process in which the carbon-dioxide is converted into sugars using the sun light energy, as this process uses carbon-dioxide and water, the resulting gas oxygen is given out as a waste product. During the night, as the photosynthesis process does not take place it exhales the carbon-dioxide itself.

Notes:
A fossil is the naturally preserved remains or traces of organisms that lived in the geologic past. There are two main types of fossils; body and trace. Body fossils include the remains of organisms that were once living, and trace fossils are the signs that organisms were present (i.e. footprints, tracks, trails, and burrows).

Notes:
According to the Red list of 2012, Ganges River Dolphin is one of critically endangered species in India. Endangered species in India comprise large varieties of rare species of wild animals, aquatic animals and insects.

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Oviparous is a zoological term that refers to animals that lay eggs which then hatch externally. Oviparous animals may fertilize their eggs either externally or internally. Frogs are oviparous since they lay eggs, which then develop outside of the mother. Ovoviviparous animals are relatively uncommon, sharks are most well-known.

Notes:
Pulse, in botany, is a common name for members of the Fabaceae (Leguminosae), a large plant family. Pulses, high in protein, are used as food for humans and other animals. Besides, they play a key role in crop rotation due to their ability to fix nitrogen.

Notes:
Palynology is the scientific discipline concerned with the study of plant pollen, spores, and certain microscopic planktonic organisms, by this way diatom, in both living and fossil form. It is associated with the plant sciences as well as with the geologic sciences, notably those aspects dealing with stratigraphy, historical geology, study of organic microfossils (palynomorphs) extracted from ancient coals, paleontology and archaeology.

Notes:
Vitamin E is a fat soluble vitamin that is essential in many physiological processes. It plays an important role in the health and maintenance of proper reproductive system function. Without vitamin E the body cannot reproduce. It is also essential during pregnancy and is needed for the proper health and development of the fetus.