An igret (a type of bird) eats the insects kicked up by the cow as it moves. The egret gets food while the cow is not affected. What type of relationship do you think this is? Why?

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.