Final answer:
Slow twitch fibers are rich in capillaries, mitochondria, and myoglobin, and can sustain aerobic activity. Fast twitch fibers contract rapidly and powerfully but fatigue quickly. Slow twitch fibers are used in endurance activities, while fast twitch fibers contribute to muscle strength.
Step-by-step explanation:
Type I slow twitch fibers, also known as slow oxidative or red muscle fibers, are rich in capillaries, mitochondria, and myoglobin. They can carry oxygen and sustain aerobic activity. Type II-B fast twitch fibers, also known as fast glycolytic fibers, have fewer capillaries, mitochondria, and myoglobin.
They contract rapidly and powerfully, but fatigue quickly. Type I fibers are used primarily in endurance activities, while Type II-B fibers contribute more to muscle strength and are relied upon in short, strenuous activities.