What is the basic unit of life?

The fundamental unit of life is the cell. Cells are the smallest structure capable of performing all the functions necessary for life, such as metabolism, energy production, growth, and reproduction. They can exist as independent organisms, like bacteria, or as part of multicellular organisms, like plants and animals.

The organization of biological systems starts at the cellular level, where the interactions within and between cells facilitate complex processes. Cells contain the machinery and genetic material necessary to carry out life-sustaining processes, making them essential to all living organisms.

In contrast, other options do not represent the basic unit of life. Molecules are made up of atoms and can contribute to cellular functions but do not have life themselves. An organism is a complete living entity that consists of one or more cells, while tissue is a group of similar cells working together to perform a specific function. These higher organizational levels depend on cells, highlighting why the cell is recognized as the basic unit of life.