Question

keystone practice exam
______ are the basic building blocks of all living organisms.
tissues
organ systems
organs
cells
possible points: 1

Explanation:

In biology (a subfield of Natural Science), cells are known to be the basic structural and functional units (building blocks) of all living organisms. Tissues are groups of cells, organs are groups of tissues, and organ systems are groups of organs, so they are not the basic building blocks.

Answer:

D. Cells