The exoskeleton, unlike the human skeleton, is a tough but flexible layer that covers the body of many animals, especially invertebrates, and protists. It is important to remember that this is not formed by bones. According to the animal its composition changes.
The main function of the exoskeleton is primarily to protect the tissue and internal organs of the living being, but in some cases it prevents the growth of animals. That in these cases need to perform the ecdysis, a process in which the animal leaves its exoskeleton to increase in size, as an example of this process we have the cicada. In this context, we can confirm that the exoskeleton does not grow with arthropod throughout its life.
Equilibrium means that two forces are balanced. This is why some of the famous artwork doesn't usually have a bunch of, say, black on one side and then nothing on the other.
