Example of a man-made object that has been changed by weathering

A man-made object that has been changed by weathering is the pyramids. The pyramids in Egypt have weathered slowly because of the dryness of the desert, but they have indeed weathered throughout the years.

Explanation: Oxygen plays a very vital role in the life of aquatic animals. The dissolved oxygen in the water helps them to breathe under water.

Optimum level of oxygen for deep living animals like oysters, bottom feeders, crabs is around (1-6 mg/L), while the animals living on the upper side like fishes require a higher amount of around (4-6 mg/L).

If the oxygen concentration in the pond is not optimum, there will no aquatic life and hence, the ecosystem will be affected.

Hence, oxygen concentration affects the fishes that live in the pond to a higher extent.