X: Ozone layer destruction
Y: Mass extinction
It is an advantage because they approach their environments from all sides equally.
Skin prevents the body from getting infections
Mitosis is a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth. Mitosis is important because the organism must:
1. replace cells that have worn out or died
2. repair tissue that is damaged
3. add cells in order to grow
4. make new kinds of cells in order to develop