The cytoskeleton of a cell allows the cell to be flexible. Our human skeletons allow <em>us </em>to be flexible.
Egg, larva, pupa and adult
Answer:
The chromosomes inroduces carbon factors
Explanation:
I'm not sure how exactly you wanted this question to be answered. You're either talking about the symmetry where animals would have two legs or two arms for example and thus producing a pair of each muscle on both sides of the body, or you're refering to the development of agonistic and antaonistic muscles where each of them served a different purpose; either extending or contracting.
Answer:
Natural selection.
Explanation:
Natural selection is when organisms who are most adapted to their environment survive and pass on their genes while those with "unfit" genes die and don't get the chance to reproduce! This slowly creates a population that is most well suited to their habitat. Hope this helps again LOL! :)