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.

He likes to take a walk in the park at dusk.

Natural language processing is a technology that allows computers to understand and analyze human language.

He is writing a thesis on abiogenesis.

Natural language understanding is an important field of artificial intelligence.

We are planning to visit the nature reserve this weekend.