organizational levels of the human body

Atoms

The smallest unit of any pure substance

Molecules

• when two or more atoms combine

• They are the chemical building blocks

Organelles

A variety of tiny functioning units inside a cell

Cells

Is the smallest independently functioning unit inside of a living organism

Tissue

Is a group of many similar cells that work together to perform a specific function

Organs

Ana anatomically distinct structure of the body composed of two or more tissue types

Organ systems

Is a group of organs that work together to perform major functions

Organism

Is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life