During warmer parts of the day, fish will be found in deeper waters of a lake. Which statement best explains this phenomena with respect to the solubility of a gas?

The statement that can best explain why during the warmer parts of the day, fish are found in deeper waters of a lake is that warmth lowers the oxygen concentration near the surface.

Explanation:

Organisms in any aquatic ecosystem require oxygen to perform their functions and survive. But the availability of dissolved oxygen in water, especially at the surface, can be affected by environmental temperature.

Warm temperature decreases the dissolution of oxygen in the lake surface water, encouraging fish to move to deeper areas. Lower temperatures increase the dissolution and availability of water at the surface, so fish can be found closer to the surface when the weather is cold.

This behaviour of dissolution / availability of oxygen at the lake surface can be observed with seasonal changes or with temperature changes between day and night.