Break fluid has the ability to absorb certain amounts of water. You do need to change it after a year or two due to electrolysis. It will eat away the metals in your breaking system and cause further...
No, the fluid cannot absorb water but you can get water in your brake system and that would be bad.
--Most brake fluids used today are glycol-ether based. Glycol-ether brake fluids are hygroscopic...
One of the causes is the evaporation of water through the stomata. The majority of water taken by the roots of a plant is lost in this way.
Plants in hot climates minimise this by having few stomata