出汗的原因

We sweat to regulate (lower) our body temperature.
It works because when sweat evaporates, it takes heat away.
In other words, water (sweat) requires energy (heat)
to change from liquid to steam (gas).
And, this amount of energy is called latent heat.

Please note:
The sweat from our own body should be at the same temperature of our body temperature, so it is NOT about "heat energy transfer from object with high temperature to the object with lower temperature"

This is a bio question!