Groundwater pollution has become a serious environmental problem.

I saw various aquatic creatures at the aquarium.

We need to minimize the system's downtime.

The albatross is a seabird with long wings.

Einstein proposed the theory of relativity.

His actions always have a duality.

My younger brother caught the influenza.

This material has high corrosion resistance.

The prevention of venereal diseases is most important in safe sexual behavior.

This equation has homogeneity.