Here's why:
* Passive transport involves the movement of substances across a membrane without the expenditure of energy. This movement is driven by the concentration gradient or pressure gradient.
* Active transport requires the cell to expend energy (usually in the form of ATP) to move substances across the membrane, often against their concentration gradient.
Endocytosis and exocytosis both require the cell to use energy to transport substances.
* Endocytosis is the process of bringing substances into the cell by engulfing them in a vesicle. This requires energy to form the vesicle and move it through the cytoplasm.
* Exocytosis is the process of releasing substances from the cell by fusing a vesicle containing the substance with the cell membrane. This also requires energy to move the vesicle and fuse it with the membrane.
In summary: Endocytosis and exocytosis are active transport processes because they require the cell to expend energy.
