The brain and spinal cord coordinate the activity of the body parts. Which system do they primarily comprise?

• A. Mechanoreceptors
• B. Central nervous system
• C. Sarcomeres
• D. Tendons

Answer: (B)

The brain and spinal cord form the central nervous system, the part of the body that processes information and coordinates actions. The CNS integrates signals from the senses, makes decisions, and sends commands to muscles to produce movement and maintain posture. That coordinating role is what defines the system that includes both the brain and spinal cord.

Mechanoreceptors are sensory receptors that detect mechanical stimuli, not a coordinating system themselves. Sarcomeres are the basic contractile units inside muscle fibers, essential for force generation but not a control system. Tendons connect muscles to bones and transmit force, again not the coordinating system that sits in the CNS.