Why is human a complex organism?

The human body is so complex because it is made out of different types of cells that are grouped into different organ systems. They all have different functions and each cell is specialized to look like a specific type of cell.

For example, all of the cells that are meant to become liver cells will also become liver cells. The different cells of the human body are meant to do some essential functions. For example, there are some cells that will be in charge of getting energy from food. There are some cells that will protect the rest of the body from injury. There are also some cells that will be important for reproduction.