Question

which term describes an extensive network of tubes, sacs, and vesicles throughout a cell that provides transport as its main function?
cell membrane
endoplasmic reticulum
centriole
cell wall

Explanation:

• The cell membrane is a thin, flexible barrier that controls the movement of substances in and out of the cell, not a network of tubes/sacs for transport.
• The endoplasmic reticulum (ER) is an extensive network of tubes, sacs, and vesicles in the cell. Its main function includes transporting proteins and other molecules within the cell.
• Centrioles are involved in cell division (forming the spindle apparatus), not in transport or having a network structure for transport.
• The cell wall (in plant cells, fungi, etc.) provides structural support and protection, not transport as a main function.

Answer:

B. endoplasmic reticulum