Achemical that, in relatively small amounts, produces injury when it comes in contact with skin tissue is known as:

the more fit you are, the faster the recovery. your heart rate drops most sharply in the first minute after you stop exercising; it should then fall about 20 beats a minute—a drop of less than 12 beats a minute is considered abnormal. this “recovery heart rate” is measured as part of an exercise stress test.

d they all are treatable but they never completely go away

perspiration and respiration.