Final answer:
The Golgi Apparatus is the organelle that modifies, sorts, and packages products from the rough ER, resembling a stack of cup-shaped, hollow saucers.
Step-by-step explanation:
The organelle that primarily modifies products from the rough ER and resembles a stack of hollow saucers, one cupped inside the next, is the Golgi Apparatus. The Golgi apparatus is made up of five to eight cup-shaped, membrane-covered discs called cisternae. It functions like a cellular post office, modifying, sorting, and packaging different substances for secretion out of the cell, or for use within the cell.
The Golgi apparatus works closely with the rough ER, where it receives proteins in transport vesicles. After modifying the proteins, the Golgi apparatus then sorts and packages them into vesicles that can either be transported around the cell or secreted outside the cell. This organelle is especially large in cells that synthesize and secrete large quantities of materials, such as antibody-producing cells in the immune system.