Cell membranes are made up of a bilayer of phospholipids that are very selective about what substances can pass through. The table below shows the different types of molecules that can enter a cell. It compares the concentration on the outside to the inside of the cell, its relative size, and whether it is polar, nonpolar, or an ion. Determine how each molecule can pass into the cell. Is it by passive transport, active transport, or endocytosis? (3 points)