During an important effort they release salt.
yes, but you have to work out really hard to get there.
All salt water organisms.
Yes, athletes perspire and eject electrolytes from their body. These essential electrolytes must be replenished, just like the body's need for water. Sodium (salt) and some other elements like potassium and magnesium are electrolytes. The ratio between water and electrolyte content in the blood needs to be in balance, or else too much water can kill you, too much sodium (salt) can kill you too.
Because your body needs essential sugars and salts to function. E.g the kidney needs some salt.
People should eat less salt as they get old.
This depends only on your needs for the concentration.
water, salt and no peeing in the reef
use less salt so you don't get a heartattack grampa
You can make it tasty. Salt is a preservative too.
the place that needs the salt rocks
People with digestion problems. --------- All the peoples and animals needs sodium chloride.
Everybody needs salt. Check the salt content of its food; if it's normal, it must be something wrong with its metabolism.