Question

multiple choice question
the smooth endoplasmic reticulum is composed of _______ within the cell.
membranes with ribosomes
a tubular network
microcompartments
folded membranes

Explanation:

The smooth endoplasmic reticulum (SER) is characterized by a network of tubules. It lacks ribosomes on its surface, differentiating it from the rough endoplasmic reticulum. Microcompartments are different cellular structures, and while the endoplasmic reticulum has membranes, it's specifically the tubular - network structure that defines the SER. Folded membranes are a more general description and not as specific as the tubular - network description for SER.

Answer:

B. a tubular network