Which of the following chemicals opens us binding sites allowing muscle filaments to connect to each other? select one:
a. atp
b. glucose
c. sodium
d. calcium

The correct answer will be option-D.

Explanation:

Calcium plays an important role in muscle contraction as they are released from the sarcoplasmic reticulum after they receive electric impulse.

Calcium triggers the muscle contraction cycle as these calcium ions bind to the troponin-tropomyosin complex. This binding exposes the myosin-binding site on the actin on which high energy myosin binds and cross-bridge is formed.

This cross-bridge formation causes the contraction of the sarcomere and therefore muscle contracts.

Thus, option-D is the correct answer.

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.

where in your body is there an enzyme that does function at a high or low ph? what is the name of that enzyme and its function?