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.
Geology is a branch of natural science that studies rocks, how they form, etc.
This field of study enabled us to know the age of Earth, the different layers that make up earth amongst many other things.
Hope it helped,
BioTeacher101
(If you have any questions, feel free to ask them in the comments)
The answer is A. The insulin, like many hormones binds to cells through receptors found on the cell membrane
