Final Answer:
Muscle contraction is triggered through the alpha motor neuron to resist further stretching. Option A is answer.
Step-by-step explanation:
When a muscle experiences stretching, a reflex known as the stretch reflex is initiated to prevent overstretching or injury. The alpha motor neuron, stimulated by the stretching of muscle spindles, sends signals to contract the muscle. This reflexive contraction is a protective mechanism designed to resist sudden changes in muscle length. The stretch reflex is part of the larger neuromuscular control system that helps maintain posture, stability, and coordination.
Option A, "Muscle contraction," is the correct answer, as it accurately describes the response triggered through the alpha motor neuron to resist further stretching and maintain the integrity of the muscle. This mechanism is vital for ensuring proper muscle function and preventing damage due to excessive stretching.
Option A is answer.