What do the four kingdoms have in common

The most common classification creates four kingdoms in this domain: Protista, Fungi, Plantae, and Animalia. These domains are further divided into a lot of smaller categories: phyla (singular: phylum), classes, orders, families, genera (singular: genus), and species.

Explanation:

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.