I believe is the thermoreceptors present in the skin as well as part of the brain called hypothalamus.
The reason that the edges of the leaves have water droplets is because plants lose most of their excess water through the stomata. this process is also called as transpiration. This can be seen mostly during the early morning time. I hope the answer comes to your help.
It's the proteins that cause the egg white to solidify when you cook it. If you keep the heat turned up too high or too long when you cook an egg, the proteins in the egg white form more and more bonds, squeezing some of the water out of the protein network and making the egg white rubbery.
