What term describes the fundamental building blocks of all living organisms?

The term that describes the fundamental building blocks of all living organisms is cells. Cells are the smallest units of life that can function independently and perform all necessary biological processes. They are the basic structural and functional units of any living organism, capable of carrying out life-sustaining activities such as metabolism, growth, and reproduction.

Molecules refer to groups of atoms bonded together and can form various structures within cells, such as proteins and nucleic acids, but they do not constitute the building blocks of life on their own. Tissues are made up of groups of similar cells that work together to perform a specific function, and organs are composed of different types of tissues that perform complex functions. Therefore, while molecules, tissues, and organs are crucial components of living organisms, it is the cell that is fundamental to the organization of life itself.