Name the three types of blood cells?

Red blood cells, white blood cells, platelets

The three types of blood cells are red blood cells which carries oxygen to places in your body. White blood cells help fight diseases and viruses. Platelets help traps things to go inside your body.

Cell division is important to single celled organisms because it allows the cells to reproduce. through cell division, cells make exact copies of themselves. when single celled organisms go through cell division, they make exact copies of themselves which is how they reproduce.

Mitochondria produce atp, a high energy compound. atp is used for all sorts of enzyme-mediated reactions, such as making proteins/nucleotides/etc, certain compounds cross the cell membrane, muscles move, etc.  without this source of energy, a cell will die. it will not be able to repair itself, defend against pathogens, etc.