Water.
osmosis always refers to the diffusion of WATER down a concentration gradient.
diffusion can be applied to any substance;
osmosis only applies to the diffusion of water.
in the situation described, osmosis occurs by water diffusing out of the plant, down the diffusion gradient (because the salt water effectively has a lower concentration of water than in the plant) and into the salt water.
The Activation Energy is the energy required before the reaction activates.
So the answer is "The additional energy required for reactions to occur spontaneously"
c. Deoxyribose:RNA I think that's right I hope it is I'm sorry if I got it wrong