The answer to your question is: Detection and reaction to stimuli in the environment
If you are going from a high gradient to a low gradient it’s passive transport. Think of a hill if you put a rock at the top of that hill it will go down no energy involved. Active transport is going up the hill you must use energy to push that rock up the hill because it’s from a low gradient to the top. Hope this helps
<span>They are more abundant than the nitrifying bacteria and may turn out to play an important role in the nitrogen cycle. Many legumes, in addition to fixing atmospheric nitrogen, also perform nitrification — converting some of their organic nitrogen to nitrites and nitrates.</span>