Which of the following body systems acts as a fast-acting control system for the body?

• A. Respiratory system
• B. Endocrine system
• C. Nervous system
• D. Digestive system

Answer: (C)

Verified step by step guidance

1. Step 1: Begin by understanding the role of each body system mentioned in the problem. The respiratory system is responsible for gas exchange, providing oxygen to the body and removing carbon dioxide. The digestive system processes food to extract nutrients and energy. The endocrine system regulates long-term processes like growth, metabolism, and reproduction through hormones.
2. Step 2: Recognize the key phrase in the question: 'fast-acting control system.' This indicates a system that can quickly respond to changes in the environment or internal conditions.
3. Step 3: Compare the nervous system to the endocrine system. While the endocrine system uses hormones to regulate processes, it is slower because hormones travel through the bloodstream. The nervous system, on the other hand, uses electrical signals to transmit information rapidly between the brain, spinal cord, and peripheral nerves.
4. Step 4: Recall that the nervous system is divided into two main parts: the central nervous system (CNS) and the peripheral nervous system (PNS). Together, they coordinate immediate responses to stimuli, such as reflex actions or sensory input processing.
5. Step 5: Conclude that the nervous system is the fast-acting control system for the body, as it is designed to quickly detect, interpret, and respond to changes in the environment or internal conditions.