What is called when a plant cell is placed in salt water and water moves out of the cell?

• A. Diffusion
• B. Active transport
• C. Osmosis
• D. Endocytosis

Answer: (C)

When a plant cell is placed in salt water, the phenomenon that occurs is osmosis. Osmosis is the movement of water molecules through a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration. In this case, the salt water has a higher concentration of solute (salt) compared to the inside of the plant cell. As a result, water moves out of the cell to balance the concentrations on both sides of the cell membrane.

This process is critical for maintaining cellular health, as excessive loss of water can lead to plasmolysis, where the cell membrane pulls away from the cell wall. Osmosis helps regulate the internal environment of the cell and is essential for processes such as nutrient absorption and waste removal.

In contrast, diffusion refers to the movement of particles from an area of high concentration to an area of low concentration, and while it is a related concept, it specifically pertains to solute particles rather than water. Active transport involves the movement of substances against a concentration gradient, requiring energy, and is not relevant when simply looking at the passive movement of water. Endocytosis is a process by which cells engulf material from the outside environment, which also does not apply in this situation where water is