Final answer:
Animal cells maintain osmotic equilibrium by controlling the movement of water molecules. They shrink in hypertonic solutions and swell in hypotonic solutions. Mechanisms like vacuole contraction and salt secretion help maintain osmotic balance.
Step-by-step explanation:
Osmosis is the diffusion of water across a membrane in response to osmotic pressure caused by an imbalance of molecules on either side of the membrane. Animal cells maintain osmotic equilibrium by controlling the movement of water molecules. When animal cells are placed in a hypertonic solution with a higher concentration of solutes than the cytoplasm, water will leave the cells, causing them to shrink. On the other hand, when animal cells are placed in a hypotonic solution with a lower concentration of solutes, water will enter the cells, causing them to swell and potentially burst. To maintain osmotic equilibrium, animal cells use various mechanisms, such as the contraction of vacuoles or secretion of excess salt in marine animals. These mechanisms help regulate the movement of water and maintain the balance of solutes inside and outside the cell.