What does increased permeability refer to?

Increased permeability refers to the ability of a membrane to allow substances, particularly fluids, to pass through it more easily. When permeability is enhanced, it means that the membrane is more "leaky," allowing a greater flow of water, ions, and other solutes. This can occur due to various factors such as changes in temperature, chemical composition, or the presence of specific receptors that facilitate transport.

In contexts like cellular biology, for instance, increased permeability can play a significant role in processes such as nutrient absorption and waste elimination, as cells respond to their environment by controlling what enters and leaves. Therefore, the correct choice is the one that highlights this aspect of increased permeability—its role in facilitating the passage of fluids through a membrane.