Water loss in frogs and toads through the skin primarily occurs through evaporation. Since amphibians like frogs and toads need to keep their skin moist for breathing, they lose water rapidly through the skin surface due to evaporation, particularly when they are in dry environments. 

Frogs and toads primarily absorb water through their skin via a process called osmosis; water moves from the surrounding environment (typically with a lower solute concentration) into their bodies through the permeable skin, driven by the concentration gradient between the water and their bodily fluids. 

In summary, water loss is by evaporation while water intake is via osmosis. Option A is the correct answer.