The same action may take place in the morning when the rising sun warms the upper layers.

Who knows what's happened in the upper layers of the earth's atmosphere.

Pressure at any point on the upper layer forces the two layers into contact.

It was used to study the upper layers of the atmosphere, Earth and the outer space.

They cause the upper layers of the skin to shrink.

It's only the upper layers of skin that are burned.

The upper layer hadn't been this long when I met him.

It is the upper layer of two in the iris.

The reason for this lies in the behavior of the upper layers.

Most animals and plants live in the warm upper layer.