C. loud noise or music because infection and injury do not occur often and aging wouldn't make any sense.
Please write your question properly
Frequency, Intensity, Time, and Type (FITT)
The answer is : increased resistance need to be added to the muscles.
Muscle conditioning refer to muscle strength and endurance. In order to improve it, you need to put your muscle in a harsher condition in a harsher condition than it used to be, so your muscle could adjust to it. That's why you should keep increasing the resistance
The answer is D pulse oximeter
hope this helps
