<span>Well active transport absolutely moves substances against their concentration gradient (answer C), although I dislike how the other answers could probably be argued for. This seems to be a case of pick the "best" answer</span>
The answer is c hope i helped
You have elevation differences<span> on </span>mountains<span> and elevation </span>differences<span>in the </span>valley<span>. The </span>valley<span> is just not as pronounced.</span>