Final answer:
The Golgi apparatus is responsible for the modification and packaging of proteins from the rough endoplasmic reticulum.
Step-by-step explanation:
The organelle that modifies and packages proteins produced in the rough endoplasmic reticulum is the Golgi apparatus. Proteins synthesized on ribosomes attached to the rough ER are transported to the Golgi apparatus, where they go through a process including organization, modification, packaging, and tagging. The Golgi apparatus also handles the production of new organelles like lysosomes and assists with the process of exocytosis, by which some of these products are exported from the cell.