Understanding chemical equilibrium is very important in understanding chemical reactions.

This substance undergoes a chemical change when heat is applied.

In this experiment, you can observe a chemical reaction.

He is a famous author, and his works are loved by many readers.

He is an excellent doctor.

My spouse is a doctor.

There were water striders floating on the pond.

The hippopotamus is a very rare animal.

A whirligig beetle is swimming in the pond.

A water spider can walk on the surface of the water.