Answer: The answers seem correct.
1. Active transport - the process in which energy is used to move the particles of a substance against a concentration gradient from a region where they are in lower concentration to a region whey are in higher concentration.
2. The answer chosen for #2 makes sense because energy is usually needed when you putting effort into doing an activity that includes some type of force. That means ions are using energy to be moved against the concentration gradient.
3. Volume makes sense for the last question since the cells are using a space (volume) to move material in and out by diffusion. The other options besides volume are unreasonable.
