Question

which is made of protein fibers that form the cells supporting network?
a) cytoskeleton
b) plasma membrane
c) cell wall
d) endoplasmic reticulum

Explanation:

The cytoskeleton is a network of protein filaments that provide structural support to the cell. The plasma membrane is mainly composed of a lipid - bilayer with embedded proteins and is not a supporting network of protein fibers. The cell wall is made of substances like cellulose (in plants) or peptidoglycan (in bacteria) and not protein fibers for support. The endoplasmic reticulum is a membrane - bound organelle involved in protein and lipid synthesis, not a supporting network of protein fibers.

Answer:

A. cytoskeleton