Are living things are made up of cells that perform the basic functions of life. And why?

Yes living things are made up of cells.

though we cannot feel cells but cell is the fundamental unit of living. cells are very tiny and are in millions of numbers.

The first person to study and discover about living cell was Robert Hooke.

cells are both structural and functional unit of living organism. which makes possible for a host cell to have a rigid body rather a fragile and weak. and it's coordinates the daily activities command down by brain through tissue cells and muscles