The correct answer is Active transport moves substances against the concentration gradient.
Explanation:
The principle difference between active transport and facilitated diffusion is that active transport helps in the movement of various substances in the uphill direction which means against the concentration gradient.
In simple words active transport helps in the movement of substance from the region of low concentration to a region of high concentration.
On the other hand during facilitated diffusion substances move along their concentration gradient which means from the high concentration region to the region of low concentration until the concentration of both sides become same.
