The placenta and the umbilical cord
I believe it is the crust
B) Hemogoblin
I’m pretty sure
Hope that helps :)
I'm not completely sure but I came up with Carbon dioxide, methane, water vapor, and nitrous oxide. I hope this is right and maybe helps you. Good luck!!
A. Skeletal and muscular
the other three don’t have to do with this type of internal movement though as the abdominal region and internal organs don’t have to do with this, A is the only possible answer