What is the order of complexity from simplest to most complex in biological systems?

The order of complexity from simplest to most complex in biological systems begins with the atom, which is the basic unit of matter. Multiple atoms can combine to form molecules, which are then organized into cells, the fundamental units of life.

After cells, which can consist of various organelles working together, we move to tissues. Tissues are groups of similar cells that perform a specific function. Next in complexity are organs, which are structures composed of different types of tissues that work together to perform more complex functions. Finally, organ systems are composed of multiple organs that coordinate their activities to perform a broader function necessary for the organism's survival.

This hierarchical structure demonstrates the increasing complexity, as each level builds on the previous one. Understanding this organization helps explain how life is structured and how different levels interact to sustain biological processes.