Which is an example of an internal stimulus?

a) a sudden change of air temperature

b) an artificial light that attracts insects

c) an increase in the amount of water available to a plant

d) a decrease in oxygen levels in the blood during exercise

D) a decrease in oxygen levels in the blood during exercise

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.