Answer:
Step-by-step explanation:
Cells need checkpoints to ensure that no error is present in the DNA or even in the cellular surroundings. It is critical that all "boxes" are checked before continuing because this ensures that no major errors are faced down the line. Cells are basic unit of life so if cells are not accurate or full of errors then tissues are affected, which affects organs, and eventually organ system and in final the whole organism. Thus, checkpoints ensure that errors are caught early and dealt with properly.
If cell did not get checked at certain phases, mistakes would go by unnoticed which could affect the whole organism (see my explaination above). Also, checkpoints ensure that cell growth is controlled (that is unwanted replication do not occur). If there are no checkpoints then cell can continue to grow and eventually uncontrolled growth of cells is referred to as cancer.