If atoms are the building blocks of molecules, cells are the building blocks of the body. Cells are the basic structural and functional units of life, and they all work to maintain the body's internal balance of homeostasis. They are capable of responding to changing conditions, changing their internal structure and processes, and dividing into new cells. Humans are made of many trillions of cells, with varying functions, allowing us to think, feel, and function. This section will go into detail about the form and function of a model cell.