Questions: Multiple Select Question Select all that apply Which transport mechanisms are classified as active mechanisms? Osmosis Filtration Active transport Diffusion Endocytosis Exocytosis

The answer is all three: Active transport, Endocytosis, and Exocytosis.

Explanation for each option:

1. Active transport: This is a process that requires energy, usually in the form of ATP, to move substances across a cell membrane against their concentration gradient. This is a classic example of an active mechanism because it involves the direct use of energy to transport molecules.

2. Endocytosis: This is an active mechanism where the cell membrane engulfs extracellular material, forming a vesicle that brings the material into the cell. This process requires energy to rearrange the cytoskeleton and membrane, making it an active transport mechanism.

3. Exocytosis: This is the process by which cells expel materials in vesicles that fuse with the plasma membrane. Like endocytosis, exocytosis requires energy to transport vesicles to the membrane and to facilitate their fusion, classifying it as an active mechanism.

In summary, all three mechanisms—active transport, endocytosis, and exocytosis—are classified as active mechanisms because they require energy to move substances across cell membranes.