An allosteric mechanism is used in the early stages of signal transduction. How is this process similar to allosteric control of enzyme activity?

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.

the missing space is phylum

the correct answer was location c, because earth is tilted away from the sun at this time