Answer:It is very harmful for our lungs and can cause cancer
Explanation:
The answer should be C. Teens have higher risk. :))
<span>D. An ideal range to aim for when exercising, calculated using the maximum heart rate formula. id the answer</span>
Answer: Between the first and second heart sounds of the cardiac cycle, systole is a time of contraction of the heart's ventricles (the sequence of events in a single heart beat).
Explanation: