Final answer:
The Golgi apparatus functions to modify, sort, and package substances for secretion out of the cell or for use within the cell. It acts as a post office, packaging and labeling items before sending them to different parts of the cell.
Step-by-step explanation:
The function of the Golgi apparatus is to modify, sort, and package different substances for secretion out of the cell or for use within the cell. It is responsible for receiving products from the rough endoplasmic reticulum (ER), modifying them, and then releasing them by repackaging into new vesicles. The Golgi apparatus is often compared to a post office, as it packages and labels items before sending them to different parts of the cell.