Answer AND Explanation:
ROUGH ENDOPLASMIC RETICULUM
This is a system of parallel flattened cavities and tubes with dense globular particles attached on the outer surface called ribosomes. They isolate and transport the synthesized protein to other parts of the cell.
SMOOTH ENDOPLASMIC RETICULUM
Not continuous with rough ER and its cavities are tubular. Involved in synthesis and transport of lipids and steroids.
