What are the roles of troponin and tropomyosin?

Troponin is the sarcomeric Ca2+ regulator for striated (skeletal and cardiac) muscle contraction. On binding Ca2+ Tn transmits information through structural changes throughout the actin-tropomyosin filaments, activating myosin ATPase activity and muscle contraction. troponin moves tropomyosin, exposing myosin binding sites on actin. myosin heads attach to binding sites on actin. Tropomyosin covers myosin binding sites on actin.

E

Explanation:

There was no set pattern in the graph involving beak depth, only that the population decreased immensely.