This is a fake painting.

This mineral is very rare.

This toothpaste contains fluoride.

On cold nights, a warm quilt is necessary.

He is an expert in nuclear physics.

In chemistry class, I learned about basic oxides.

In chemistry class, I learned about acidic oxides.

Bioweapons are a major threat to humanity.

In this experiment, we will use various inorganic compounds.

In this experiment, we will observe the reaction of organic compounds.