Demography is the statistical study of human population.

A saprophyte is an organism that lives on or in a non-living organic matter, secretes digestive enzymes into it and absorbs the products of digestion.

Ornithology is the scientific study of birds.

Adaptation is the heart and soul of evolution. Evolution is the change in a population over time. Many adaptations are necessary for evolution to work. An adaptation, also called an adaptive trait in biology, is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection.

Red Data Book is the IUCN Red List of threatened species. It is also known as the IUCN Red List or Red Data List.

Biogas comprises primarily methane and carbon dioxide and may have small amounts of hydrogen sulphide, moisture and siloxanes.

Rhizobia are soil bacteria that fix nitrogen (diazotrophs) after becoming established inside the root nodules of legumes.

Mangroves are various types of trees upto medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics, i.e. mainly between latitudes 25° N and 25° S.

SPM stands for Suspended Particulate Matter.

Eye irritation can be avoided by cutting onions under running water or submerging the onions in a basin of water. Leaving the root end intact also reduces irritation as the onion base has a higher concentration of sulphur compounds than the rest of the bulb.

Carbon dioxide is a by-product of respiration, which is carried out by all organisms all the time, even at night.

Yellow revolution is associated with the large scale production of oil seeds.

Vermiculture means worm growing or worm farming. When earthworms are used primarily for the production of compost, the practice is referred to as vermicomposting.

Red soil indicates the presence of iron oxides.

Blizzards are severe winter storms characterised by heavy snow and strong winds. When high winds stir up snow that has already fallen, it is known as a ground blizzard. Blizzards can impact local economic activities, especially in regions where snowfall is rare.