From what I can tell, The answer is either A or B. Mammals have what is called an Endoskeleton, which means that their skeletons are inside their bodies. A way to remember this is Exo- is similar to exit and when you exit something then you are going outside. Endo- sounds like into, which can relate to being on the inside. Insects have Exoskeletons, which are made from Chitin. Now Agonists are also called Prime Mover muscles, which means they are practically the same thing.
An autotroph is an organism that can build its own food
Rolls in mud to cool off and deter flies
