Why is the cell called the structural and functional unit of life?

The cell is called the structural unit because every living organism's body is built out of cells, just like a brick wall is built from bricks. Whether it is a tiny bacterium or a huge elephant, the body structure is made of one or many cells. It is called the functional unit because all the life processes such as nutrition, respiration, excretion and reproduction actually happen inside cells. Even in a big multicellular body, each tiny activity is carried out at the cellular level, then coordinated for the whole organism. So no smaller part can independently show all the signs of life. Because the cell does both jobs, building the body and carrying out its functions, we call it the structural and functional unit of life.