Submerged Aquatic Plants Can Take Up CO₂ from the Water

Submerged aquatic plants can take up CO₂ from the water in all of the following ways, EXCEPT

A) diffusion through stomata.
B) direct diffusion of ambient CO₂ from water across cell membranes.
C) active transport of bicarbonate into the leaf followed by conversion to CO₂.
D) excretion of carbonic anhydrase into the water, followed by uptake of the resulting CO₂.