What might make it hard for someone to use a dichotomous key? make a list of possible reasons.

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.

b) the inside picture would look at a very high temperature in a very low ph