The molecule will enter the cell using a channel protein.
Selective selection,since being smaller is an advantage the rabbits got smaller similar to evolution
Well, the food is in the environment. I would like to compare it with how bacteriae feed (however my biology is quite rusty), that is, they engulf their food and they "digest" -- not the proper term, since there are no organs to do real digestion -- it.
A - Endoplasmic Reticulum.