Answer:
B.Lubricating cartilage at joints
the answer is A. I took the test and got it right. The question is specifically asking about the THIN filaments, making it actin- and only actin.
The first one is going to be b and the second one is going to be a
The ATP is the adenosine triphosphate. The ATP molecule has the three phosphate molecules attached with the adenosine. The ADP is the adenosine diphosphate. It has two phosphate groups. The number of phosphate molecules is responsible for the amount of energy in bonds. Hence the ATP molecule has the three phosphate group hence it has more stored energy as compared to the ADP molecule which has two phosphate group.