Final answer:
During muscle contraction, the I bands shorten the H zones disappear, myosin heads bind to actin, and ATP is hydrolyzed. However, the concentration of hemoglobin in muscle fibers does not increase during muscle contraction. The option (D) is correct.
Step-by-step explanation:
During muscle contraction, several events occur. The I bands shorten and the H zones disappear, resulting in the shortening of the sarcomere. Myosin heads bind to actin, creating cross-bridges that pull on the actin filaments. ATP is hydrolyzed as a source of energy for muscle contraction. Finally, calcium concentration in the sarcomere increases, which triggers the exposure of binding sites on the actin filaments.
In muscle contraction, there is no direct effect on hemoglobin concentration in muscle fibers. Hemoglobin is responsible for carrying oxygen in the blood, and its concentration does not change during muscle contraction. Therefore, option (D) is correct.