Why is topsoil essential to conserve and protect?

(a) Topsoil holds subsoil in place, preventing landslides.

(b) Plants require topsoil to grow—and plants are vital because they provide food and oxygen and they absorb carbon dioxide, thereby protecting climate.

(c) Topsoil is derived from fossil fuels, which means it is expensive and rare.

(d) Plants grow poorly in the subsoil that remains when topsoil is eroded.