cell is basic unit of life as when we are going to build our home we need bricks similarly our body is made up of cells which performs all activities required in our lifestyle. Some organisms are made up of single cell they are called unicellular. For eg.- amoeba, protozoa, bacteria, etc. Whereas some organisms are made of many cells , they are known as multi-cellular organisms. For eg.- humans, animals, birds, etc. Thus, cell is basic and structural unit of life.