Why do fetal cells continue to proliferate while fully differentiated adult cells lose their ability to divide?

Show Answers

Adult cells contain numerous cyclin inhibitors that block progression into the S phase.Fetal cells lack phosphatase enzymes.Proteinase enzymes are missing in fetal cells.Cyclin-dependent kinases are not present.

Explanation

Fetal cells keep dividing because adult cells have multiple cyclin inhibitors that prevent them from entering the S phase of the cell cycle, thereby halting division in terminally differentiated cells. The other options incorrectly attribute the cause to missing enzymes or kinases.