Organisms are made of parts that work together to form a living system. The smallest functional unit of life in an organism is known as
OA a cel
ОВ.
an organ system
OC
a tissue

A. a cell

Explanation:

Cells are the building blocks of life, or, the smallest unit of life. Cells join to make tissues, and tissues join to make muscles, and muscles join to make an organ system. This means that it can't be either of the other two options.

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