Which of the following is a key difference between rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER)?

✓ Correct Answer: Option B

Rough ER is characterized by ribosomes on its surface, which are essential for synthesizing proteins destined for secretion or insertion into membranes. Smooth ER lacks ribosomes and is involved in lipid synthesis, detoxification, and calcium storage.