10. You should not devote time for rest when you exercise.​

Specifically, rest is essential for muscle growth. Exercise creates microscopic tears in your muscle tissue. But during rest, cells called fibroblasts repair it. This helps the tissue heal and grow, resulting in stronger muscles.

answer; /// i believe that the correct answer is (c); ///when the lungs expand, they fill with air from the atmosphere;

teens need 8-10 hours of sleep. it kind of depends on what time you get up. but prob around 10 or 11 p.m. or 11 or 11: 30 p.m.