stages of life cycles

When all the hydrogen gets exhausted, fusion stops and as a result the internal pressure, which keeps the star from collapsing under its high gravitational force decreases and the core contracts under its own gravity. However, the hydrogen in the outer shell fuses to helium and releases energy. Bu..

The Life of a Star - 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 o..

Evolution by Stages - The evolutionary process has developed over millions of years. Lineages evolved and split and modifications occurred gradually in stages. Life has been in existence on Earth for at least 3.5 billion years but the first two stages of evol..

Water is an indispensable commodity of life. Water determines the distribution, structure and function of organisms in the ecosyste..

Water is an indispensable commodity of life. Water determines the distribution, structure and function of organisms in the ecosystem. Water occurs in three phases - solid, liquid (ice/snow) and gaseous (water vapour). In liquid phase it is vital for the existence of life on this..

Nitrogen is an important structural component of many necessary compounds, particularly proteins. Atmosphere is the reservoir of free gaseous nitrogen and nitrogen compounds are found in bodies of organisms and in the soil. Living organisms cannot pickup elemental gaseous nitrogen directly from the..

Every cell that is capable of undergoing division passes through a cyclic sequence of events involving growth and division. It is called Cell Cycle. It encompasses the entire sequence of events that occur in a cell from the time it is formed from its parent cell till the time of its own d..

Earth is the source of matter for all living organisms, as they require several (about 40) elements for their growth and life processe..

Oxygen Cycle - 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 rocks. Dissolved oxygen in water is the source of oxygen for aquatic organisms..

Biogeochemical Cycles - Earth is the source of matter for all living organisms, as they require several (about 40) elements for their growth and life processes. Some elements and their compounds have an important role in the living protoplasm and are required in large amounts. T..