Which of the following describes osmosis?
a. Oxygen transfers into red blood cells through small gaps in the cell membrane from the oxygen- rich environment surrounding the cells
b. Large molecules are brought into the cell by wrapping the cell membrane around the molecules to form a vacuole.
c. Water moves across the cell membrane from the side with high osmotic pressure towards the side with low osmotic pressure.
d. Membrane proteins provide a pathway for larger particles to move across the cell membrane and bring the cell and environment closer to equilibrium.

Osmosis is a good example of passive transport. In this transport across the cell membrane without any input of cellular energy movement of atomic substance occurs.

Osmosis is defined as the movement of water across the selectively permeable cell membrane from the high osmotic pressure potential towards the area of low osmotic pressure potential. Some examples of osmosis are skin soaking up water, plants receiving water, and when exposed to freshwater red blood cells swelling up.