Sucking is a very natural activity for a baby.

I am sure the heat, and not the natural, beautiful activity of her mind, is responsible for her condition.

To get together and talk is a very natural activity; it does not require regimentation of this sort.

The reef has suffered high degradation due to both natural and human activities.

There is no evidence that they once reached further and since have been shortened through natural or human activity.

What it could not be was physically destroyed by activity on the planet, natural or human.

Learning is a natural - one might say an instinctive - human activity.

They may think this is some kind of natural volcanic activity.

We also look for changes in the oceans due to natural and human activities.

Thinking was, after all, a natural activity of the mind, continuing even when not under conscious control.