All living things are made of
cells. Since humans are alive, we are also made of cells.
Cells make our body tissue. Tissue makes our body organs.
Organs make our body systems. Cells are the building blocks of
In order for
us to stay alive, our cells must stay alive. Cells need food,
oxygen, and water to remain alive and healthy.
Using the food, oxygen and water creates energy for our cells. This process makes waste in the form of urea and carbon
dioxide that must be removed from the cells.
All of the systems of the human body work together to give our cells what
they need and to remove the waste made by the cells. Keeping our
cells well keeps our bodies well.