actin and myosin collagen and tubulin hemoglobin and myoglobin amylase and polymerase
I gave my students this multiple choice question: Which two protein molecules are essential for muscle contraction and relaxation?

Only one answer is correct among these 4 choices:
- actin and myosin
- collagen and tubulin
- hemoglobin and myoglobin
- amylase and polymerase

Could you tell me which one is correct?

actin and myosin