Answer:
Muscles produce keratin so that hair can grow stronger. Sweat glands break down the food that is consumed. Muscles contract rapidly to produce heat on a cold day.
Explanation:
The subscript; the number at the bottom right of the symbol
The last suggestion is correct....when you have setes of rest in between workouts..you allow the lactic acid to seep into your muscles and ensure that the muscle protein is broken down properly.
The answer would be thermal insulator, hope it works goodluck
