Her smile is very natural, and it feels comfortable.

In philosophy, natural law refers to the moral laws of the universe.

The equilibrium length of this spring is 5 centimeters.

He prefers natural foods.

This wood may spontaneously combust if the humidity is high.

His car spontaneously combusted all of a sudden.

Natural rights are rights that humans have from birth.

Gender identity refers to the gender that each individual recognizes themselves as.

Neurotransmitters are responsible for transmitting information between nerve cells.

Chemotransmitters play an important role in the transmission of information between nerve cells.