Final answer:
The statement regarding C fibers and A delta fibers is true. The proportion of slow-twitch to fast-twitch muscle fibers varies among individuals, and athletes like sprinters and marathon runners have different fiber compositions suited to their sport.
Step-by-step explanation:
The statement that C fibers carry at a rate of 0.5-2 meters/sec, while A delta fibers carry at a rate of 5-30 meters/sec is True. C fibers are unmyelinated and conduct impulses slowly, typically involved in transmitting dull, aching pain. In contrast, A delta fibers are myelinated, which allows for faster transmission of impulses and they are associated with sharp, acute pain.
Regarding muscle fibers, the true or false notion that all people have the same proportion of slow-twitch to fast-twitch muscle fibers is False. Individuals vary in their proportion of muscle fibers, and factors like genetics and training can influence this composition.
Professional sprinters are likely to have a higher proportion of fast-twitch muscle fibers, which are suited for quick, explosive movements and fatigue faster. In contrast, professional marathon runners are likely to have a higher proportion of slow-twitch muscle fibers, known for their endurance and ability to contract for extended periods.