Salt concentration is the factor among the following factors given in the question that does not vary between a fast flowing river and a pond that receives no water input. The correct option among all the options that are given in the question is the second option. I hope the answer comes to your help.
Does this help?
<u><em></em></u>
<u><em>The glucose (sugar or plants food) is then converted back into carbon dioxide which is vital during photosynthesis. This therefore means that when stomata is blocked photosynthesis will stop because the CO₂ level will decline within the leaf, stopping the reactions that are light-independent.</em></u>
<u><em></em></u>
<em>~Hope this helps~</em>
