Which of the following choices is likely to include muscles or glands?

• A. Sensors
• B. Integrating Center
• C. Effectors
• D. Error Signal

Answer: (C)

The correct choice refers to effectors, which are crucial components in physiological processes. Effectors include muscles and glands that carry out the response to stimuli. When the body detects changes in the internal or external environment, the integrating center processes this information and sends signals to the effectors to initiate an appropriate response.

Muscles serve as effectors by enabling movement, whether it be skeletal muscles causing voluntary motion or smooth muscles facilitating involuntary actions like digestion. Glands, on the other hand, play a significant role in secreting hormones or other substances that regulate various bodily functions in response to signals received.

In contrast, sensors are responsible for detecting changes or stimuli in the environment, while the integrating center is involved in processing this information and determining the appropriate response. The error signal pertains to a discrepancy between the desired state and the actual state, guiding the integrating center's output but not directly involved in executing any action. Thus, when considering which components of the body directly enacts responses through muscles and glands, effectors are clearly the appropriate answer.