The natural increase rate of the population has been steadily declining.

Nature-deficit disorder is a term used to describe the negative effects of a lack of exposure to nature on physical and mental health.

A Cartesian natural transformation is a natural transformation between two functors that preserves Cartesian structure.

Cartesian natural transformations are important in category theory.

There have been numerous crimes against nature reported in the area.

Natural killer cells are an important part of the immune system.

The natural increase rates in the country have been steadily declining over the past decade.

Many children today suffer from nature-deficit disorders.

Nature deficit disorder is a term used to describe the negative effects of spending less time in nature.

Spending time in nature can help prevent nature deficit disorders.