Question

why cell is known as basic unit of life

Answer 1

Cells are the building blocks of life, they are the smallest living entities in a living organisms. They perform functions necessary for the survival of the organism, such as respiration, digestion, excretion, protection from the pathogens and so on.
Each cell performs specific functions in the body. Therefore, cells specialising in function functions are often grouped together in the body. This means that a particular function is carried out by a cluster of cells at a definite place in the body. In this way different functions are performed by different groups of cells in an organisms. This constitutes the organisation at cellular level. That is why cell is known as basic unit of life.