Final answer:
During a race, Marcy's body adjusts through sweat production and enhanced coordination between muscle groups, and she may have slow-twitch muscle fibers enhancing her endurance. Blood flow increases and blood viscosity decreases to ensure efficient oxygen and nutrient delivery to active muscles.
Step-by-step explanation:
When Marcy is running in a race, her body undergoes various physiological changes due to the anatomic structures and physiological processes that support movement and responsiveness. As Marcy's body temperature rises, her sweat glands activate to cool her down, demonstrating responsiveness. Additionally, muscle coordination is critical for her movement, particularly the action of muscle groups while running. Her musculoskeletal system will work in harmony to achieve this coordinated movement, propelled by energy metabolism that is occurring at a cellular level. During a marathon, runners like Marcy will experience an increase in blood flow to meet the muscular demand for oxygen and nutrients, leading to an overall increase in blood flow, sometimes up to 10.0 times the resting rate, and a slight decrease in blood viscosity to 95.0% of its resting value, which may help with more efficient circulation.
Marathon runners often possess a high proportion of slow-twitch muscle fibers, contributing to their endurance, so Marcy may have these as well. Such fibers are energy-efficient and fatigue-resistant, designed for long-duration activities, like running a marathon. As Marcy competes, these structural and physiological characteristics demonstrate her body's complex biological response to intense physical activity.