He has a deep interest in natural history.

His car spontaneously combusted all of a sudden.

This wood may spontaneously combust if the humidity is high.

The equilibrium length of this spring is 5 centimeters.

He prefers natural foods.

Her smile is very natural, and it feels comfortable.

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

Calculating the natural logarithm is an important part of mathematics.

Natural language processing is the technology that allows computers to understand and generate human language.

I was moved by the beauty of nature.