cells are called the basic units of life, because all living things are made from cells. (some living things are unicellular,have 1 cell, and some living things are multicellular,have more than 1 cell) human beings are multicellular, while bacteria are unicellular. Cells are called the basic unit of life because, all living things come from other living things. cells are called the basic units of life, because all living things are made from cells. (some living things are unicellular,have 1 cell, and some living things are multicellular,have more than 1 cell) human beings are multicellular, while bacteria are unicellular.