Which of these changes produces a chemical change? A. Lava cools and changes from a thick fluid to solid rock.
B. A large rock is crushed into gravel,
C. Limestone slowly dissolves in water and forms a cave,
D. A stone fizzes and forms a gas when acid is dropped on it.

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.