For his class project, mike needs to collect samples of algae. in which section of a river is mike most likely to find algae?

On the surface of rocks that are in the river!

Middle section of river.

Explanation: The algae is a diverse group of aquatic organism that is found in water and has the ability to conduct photosynthesis.

They appear green in color and found in still water, river and lakes. The most common place for the occurrence of algae is the middle part of river.

This is because the water there is not running water and the nutrients reaching river gets deposited in the middle section with adequate amount of sunlight penetrating water.

So, the correct answer is middle of river.