What are 3 reasons why a cell may stop dividing at a checkpoint?

Cells divide for the purposes of reproduction, replacement of lost or dead cells and to promote growth of the structure in which they are located. Only the first of these reasons applies to single-celled organisms, but the others are essential to the efficient functioning of a multicellular body. Hope this helps

the sphincter muscles at the end of the digestive tract is the anus.

science-ocean floors and habitats study guide by volleyballqueen3817 a major advance in ocean-floor mapping. list four sections of the ocean floor. algae that use sunlight to produce their own food through photosynthesis. all of the feeding relationships that exist in a habitat. drying out, predators, find food.