Answer:
I think the answer is option 3
Osmosis is the movement of water particles from an area of high concentration of water particles to an area of low concentration of water particles across a semi permeable membrane
Diffusion is the movement of particles from an area of high concentration of particles to an area of low concentration of particles across a partially permeable membrane
Plasmolysis is the shrinking of the cytoplasm if a plant cell in response to diffusion of water out of the cell and into a high salt concentration solution as the cell membrane would pull away from the cell wall
Hope this helped
Carbon dioxide because every other option requires an input.
The keystone species is the one at the bottom of the pyramid, if we look at it like a pyramid. If the grass dies, then the deer cannot get food and die, and the predator cannot eat and dies, and the whole ecosystem can fall apart.