Question

which of the images below represents passive transport?
○ ab and c
○ ab and d
○ ac and d
○ bc and d

Explanation:

Passive transport is the movement of substances across the cell - membrane from an area of higher concentration to an area of lower concentration without the use of energy. Image A shows simple diffusion (a type of passive transport) where molecules move directly through the lipid - bilayer. Image B shows facilitated diffusion (also passive transport) where molecules move through a protein channel. Images C and D show active transport as they involve energy input (as indicated by the energy symbol in C).

Answer:

A. AB and D