Ecosystems in the deep sea, where no sunlight can penetrate, use sulfur.

Their solid surfaces are so deep inside that no sunlight penetrates there at all.

Its name comes from how little sunlight penetrates to the bottom of the slot.

Energy comes in to the system when sunlight penetrates the top of the atmosphere.

It is near the surface, where sunlight penetrates, that the fish live and breed.

By the time he got down, sunlight penetrated even into the swamp.

Most of the trail is in a deep forest where sunlight rarely penetrates.

The sunlight cannot penetrate to more than a hundred feet.

They entered a deep, dark section of forest where the sunlight did not penetrate and the wind was chill.

He wanted a table in the back corner, where no sunlight penetrated.