Answer:
Cells → Tissues → Organs → Organ Systems.
Step-by-step explanation:
The human body is made of trillions of cells. Cells are the basic unit of life. There are many different types of cells in the human body that have varying structures and serve different, specific functions.
These cells are organized into tissues. A tissue is a group of cells that work together to serve a specific function. A tissue’s function is determined by the types of cells it is made of.
Several types of tissue work together as an organ. Different organs in the body carry out different functions. For example, the heart pumps blood throughout the body, the stomach breaks down food, and the brain controls and coordinates the activities of the body.
A group of organs will work together in organ systems that perform our life functions. For example, the stomach and small intestine work together within the digestive system to break down food and then absorb the nutrients, releasing them into the bloodstream. The heart and blood vessels work together in the circulatory system to move the blood and the nutrients it carries around the body.
Therefore, we can conclude that the order of these structures, from smallest to largest, is cells → tissues → organs → organ systems.
Hope this helps! :)