Answer: a cell wall
Explanation: a cell wall is a barrier that protects the plant cell. Animal cells do not need this becuase they have a cell membrane which also protects the cell.
Carbon dioxide and oxygen are two molecules that undergo this simple diffusion through the membrane.
Answer:
C. Vaccination
Explanation:
vaccination is the administration of a vaccine to help the immune system develop protection from a disease. Vaccines contain a microorganism or virus in a weakened, live or killed state, or proteins or toxins from the organism.
