life cycles of organisms

Oxygen is another essential element for living organisms. It is present in large quantities (20.95% v/v) in the atmosphere and is also seen in bound state in water and as oxides and carbonates in rock..

Carbon is found as graphite and diamond in nature. It also occurs as carbon dioxide in the atmosphere. Because of the position of its electrons, an atom of carbon can form covalent bonds with hydrogen, oxygen, nitrogen, phosphorus and other carbon atoms. Because of this versatility, the carbon atom..

Sulphur Cycle - Sulphur is an important component of most proteins, few vitamins and enzymes. Though sulphur occurs in gaseous form, as hydrogen sulphide (H 2 S) and sulphur dioxide (SO 2 ), the residence time of sulphur in atmosphere is very small (about 4 x 10 1 0 kg) and its main reser..

The nitrogen cycle is complex as it depends on the activities of various bacteria. Nitrate in the soil is built up by plants into protein which is then passed on to animals, which eat the plants. The nitrogen from the protein is returned to the environment as ammonia (ammonification), eit..

The life cycle of a star begins with the accretion of hydrogen and helium gas at -173 o C into smaller dense clouds, which contract under their own gravity. This dense cloud of gas contracting under its own gravity is called a Protostar. A cloud of gas from which a star is..

Living organisms have a definite organisation consisting of structural and functional units called cells that make the physical basis of life namely protoplas..

Structure and function in living systems Reproduction and heredity Regulation and behavior Populations and ecosystems Diversity and adaptations of organisms..

Structure and function in living systems Reproduction and heredity Regulation and behavior Populations and ecosystems Diversity and adaptations of organisms..

The life cycle of a star begins with the accretion of hydrogen and helium gas at -173 o C into smaller dense clouds, which contract under their own gravity. This dense cloud of gas contracting under its own gravity is called a Protostar . A cloud of gas from which a star is born..

Organism and Its Characteristics - An organism is a distinct unit of life in nature. It is said to be the smallest level and basic unit of ecological hierarc..