Skin is made up of dead cells impregnated with keratin and oil which makes our epidermis relatively impermeable but even then human tends to sweat freely during hot temperature because there are glands called sweat glands present in the dermis layer of skin.
These sweat glands have special channels or ducts that open outside the epidermis.
In summer when temperature rises these glands release sweat which evaporates and causes cooling of the body. This helps in thermoregulation. So the right answer is - sweat glands have special channels through skin.
In my opinion, there is no such things as a "safe" sport. The responsibility of the player is to be aware of their surroundings. The responsibility of the team is to not only be aware of their surroundings too, but to also look out for themselves and their teammates.
