Traits are based on improving what primary factor in organisms? * behavior
anatomy
fitness
Physiology

heat a spark and oxygen

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.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.