Answer:
Osmosis - water
Ions - diffusion
Large proteins - endocytosis
Step-by-step explanation:
Ions and small molecules can cross the cell membrane by simple diffusion, where they move from a high concentration to a low concentration, down a concentration gradient.
Osmosis is the process whereby water travels across a semi-permeable membrane from a high concentration to a low concentration.
Larger cargo can cross the membrane through a process called endocytosis, where the membrane engulfs the particles and brings them inside the cell, encased in a vesicle.