"There are essentially four basic ways a substance can get through the plasma membrane. What are they? If you get specific, you will end up listing six. That's fine too."
Phagocytosis, Pinocytosis, Endocytosis, Mediated transport (carrier proteins), Channel proteins, Passive transport (Diffusion and facilitated diffusion), are all methods for things to enter the cell. So my four would be which of these?