Explain why normal cell cycle regulation is critical to the health of both humans and animals?

Normal cell cycle regulation, for most eukaryotic cells,
is the process governing when a cell divides or doesn't, if there is something wrong
with that process and this in turn leads to mutations or mistakes in the transfer of DNA
for that division, it will lead to the death of that cell in order to prevent the
development of mutant cells.

The four stages of this cycle
include:

1-growth

2-mitosis
(or division of the nucleus)

3-
cytokinesis

4-division of the
cytoplasm

These four stages have to take place
each time the cell divides and any time the resulting daughter cells, from previous
division, divide.

If there are problems with cell cycle
regulation, those mutant cells can survive and even proliferate, leading to further
problematic divisions, leading to things like cancerous or other types of dangerous or
improperly functioning cells.

Aberrant DNA in these cells,
which is passed on thanks to the lack of a properly functioning cell cycle regulation,
can lead to all kinds of problems, not just within each particular cell but also to
cells that aren't doing their particular job, aren't growing to the right proportions,
basically anything and everything in a human or animal can be affected in a very
negative way.