Each trait of a plant is determined by . A) an allele
B) one gene
C) a pair of genes
D) one dominant gene

C) a pair of genes

Explanation:

C should be correct because each trait is controlled my multiple genes. It is very rare to see one thing being controlled strictly by one gene, rather multiple things work together to produce the traits. Living things are very amazing if you dive deep into their DNA level,

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.