How do melanocytes and keratinocytes work together to protect the skin from uv damage?

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.