Understanding chemical equations is difficult.

We are growing vegetables without using chemical fertilizers.

Oxygen, which is one of the chemical elements, is necessary for us to breathe.

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.

I found an old box in the storeroom.

In biology, neoteny refers to the phenomenon where the adult retains the form of the juvenile.

Neurotransmitters are responsible for transmitting information between nerve cells.

Sufficient caution is necessary when handling radioactive materials.