What term describes the basic structural and functional unit of life?

The correct term that describes the basic structural and functional unit of life is "cell." Cells are the foundational building blocks of all living organisms, and they perform vital functions necessary for life. Each cell contains the necessary components, such as organelles, that enable it to sustain life processes, including metabolism, energy production, and reproduction.

Tissues consist of groups of similar cells working together to perform a specific function, while organs are composed of different types of tissues that coordinate to carry out more complex tasks. Systems refer to groups of organs that work together for a common purpose, such as the respiratory or circulatory systems. Therefore, while tissues, organs, and systems are all essential components of biology, they are made up of cells, which stand as the fundamental unit of life itself.