Cation Exchange Is an Important Process That Facilitates the Uptake

Cation exchange is an important process that facilitates the uptake of nutrients by plants.How is this accomplished?

A) Cation exchange allows more incorporation of air into soil.
B) Because of the positive charge on clay particles, cation exchange gets rid of the clay.
C) Roots secrete protons (H⁺) or acids into the soil, which displace positive nutrient ions from soil particles.
D) Negative ions such as phosphate, nitrate, and sulfate are exchanged for cations.
E) Cation exchange is most effective when performed in the C horizon.