Which morphological difference is associated with C4 plants but not C3 plants? A. Stomata in the lower epidermis
B. Spongy mesophyll cells
C. Xylem
D. A waxy coating of the bundle sheath

Explanation:

D. A waxy coating of the bundle sheath

Explanation:

C3 plants are plant that make use of Calvin cycle for synthesising their food while C4 plants makes use of Calvin cycle along side a 4 carbon compound that help store carbondioxide.

The C4 plant is unique because it has both mesophyll cell and bundle sheath unlike C3 plant that has only the mesophyll cell. The bundle sheath is where the 4 carbon compound that ferried carbondioxide is first stored before in form of oxaloacetate before broken down cell into pyruvate and carbondioxide and now proceed into the Calvin cycle for the formation of sugar in the bundle sheat.

The bundle sheat and mesophyll cell help separate when carbondioxide is ferried in and when it is used up for sugar formation in C4 plants.