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.
Answer:
Fossils are the preserved remains or traces of animals, plants, and other organisms from the past. Fossils are important evidence for evolution because they show that life on earth was once different from life found on earth today
Explanation:
First one is axis, second one is light and energy (I think), medium sized star, I don't know the forth one, sorry, 1,300,000 times bigger than the earth, I don't know the sixth one, and 9940.73° F.
