Respuesta :
Answer: 1. Muscle fibers
2. Endurance activities
3. A motor unit
4. All or none
5. Skeletal muscles
6. Smooth muscles
7. Cardiac muscles
Explanation:
Answer: 1. Muscle fibers
2. Endurance activities
3. A motor unit
4. All or none
5. Skeletal muscles
6. Smooth muscles
7. Cardiac muscles
Explanation: