Answer;
-Cell
Explanation;
-The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Cells make up the smallest level of a living organism such as human beings and other living things.
-The cellular level of an organism is where the metabolic processes occur that keep the organism alive. That is why the cell is called the fundamental unit of life. Some organisms, such as bacteria or yeast, are unicellular; consisting only of a single cell, while others, for instance, mammalians, are multicellular.