Exclusively breastfed babies do not require additional water even when it is very hot outside, as long as baby is allowed to nurse as needed. Even in extremely hot, dry weather your baby can get all the liquids needed via breastmilk.
Smooth muscles contract very slowly, whereas skeletal muscles can contract at different rates. Skeletal muscles can be composed of fast-contracting fibers, slow-contracting fibers or a mixture of both.
Both cardiac and smooth are involuntary. Skeletal is voluntary. Skeletal muscles are the muscles you use to move your bones. You do these things voluntarily, like raising your arm. Skeletal muscle tires out quickly. Cardiac muscle is only found in your heart. This muscle type keeps your heart running and does not tire.