ASAP plss help me with questions 6,7 and 8 please I will give brainlist since it’s three questions

So i have a lot of answers answered but it says i still need to answer more questions. why is it doing that? how many questions need to be answered?

The bones of the extremities are parts of the a-appendicular skeleton b-axial skeleton c-long bone group d-medial skeleton

Christopher came down with chicken pox after spending time in his child’s day care. the chicken pox represents what link in the chain of transmission in this scenario?