Final answer:
The correct answer is option b. sympathetic nervous system.
Step-by-step explanation:
When Dan hurt his knee, the pain signals were carried to his brain by the nervous system, specifically the somatic nervous system. This system is responsible for transmitting sensory information and initiating movement. It is a part of the overall nervous system that includes the central system (brain and spinal cord) and the peripheral system (nerves throughout the body), working together to control the body's responses.
The example of Michelle possibly falling off her scooter illustrates how the nervous system helps maintain balance by quickly sending messages to adjust body position. In the case of pain, such as Dan's knee injury, sensory receptors detect the pain, which then travels through the nervous system to the brain, where it is processed and understood as pain.