Correct Answer:
C. Brain and Spinal Cord
Explanation:
The correct answer is Brain and Spinal Cord because these two primary structures form the main processing command center for the human nervous system.
- Step 1 (CNS Framework): The human nervous system is structurally divided into two main components: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS).
- Step 2 (Functional Overview): The CNS is entirely contained within secure skeletal cavities (the cranium protecting the brain and the vertebral column protecting the spinal cord). It acts to receive, process, integrate, and send out sensory information throughout the body.
- Incorrect Options:
- Muscles and Bones is incorrect because they form the musculoskeletal system, which provides structural movement and support rather than neurological processing.
- Blood and Lymphatic Vessels is incorrect because they comprise the circulatory and immune systems, handling fluid transport and defense.
- Skin and Hair is incorrect because they make up the integumentary system, acting as an external protective barrier.