That is true. Active transport goes against the concentration gradient. Particles want to move from higher concentration to lower concentration and even out, but active transport makes them move against that.
Of the following given choices;
A. glacial erratics B. U-shaped valleys C. unusually shaped rocks D. mudslides.
The answer is; C.
The wind carries soil particles is it blows. These soil particle hit on rocks in their path and over time gradually erode the rocks. An example of this type of erosion is the aeolian process. Usually the bottom o the rock is eroded more than the top. This is because the bottom is hit by larger soil particles that are heavier to carry by the wind. An example of rock formed in this process is attached in the picture below.
Answer: I think it's Nuclear, sorry if I'm wrong!
Explanation:
The answer to the question is A