Questions: The force of muscle contraction is controlled by multiple motor unit summation or recruitment. (A) True (B) False

The answer is (A) True: The force of muscle contraction is controlled by multiple motor unit summation or recruitment.

Explanation:

• (A) True: This statement is correct. The force of muscle contraction is indeed controlled by the recruitment of multiple motor units. A motor unit consists of a motor neuron and the muscle fibers it innervates. By recruiting more motor units, the body can increase the strength of a muscle contraction.
• (B) False: This option is incorrect because it contradicts the physiological mechanism of muscle contraction. Multiple motor unit summation is a well-established concept in muscle physiology that explains how varying the number of active motor units can control the force of contraction.

In summary, the correct answer is (A) True, as the recruitment of multiple motor units is a key factor in controlling the force of muscle contraction.