But some scientists believe that the Earth's atmosphere would never have contained the oxygen we need without plants.

The atmosphere now contains about 355 parts per million of carbon dioxide.

Stuff in the Air Find out what the atmosphere contains.

Today's atmosphere contains 21% oxygen, which is high enough for this rapid development of animals.

Shortly after the Earth was formed, the atmosphere contained very little oxygen.

The atmosphere does contain a high concentration of carbon dioxide.

When it first formed, Earth's atmosphere may have contained more greenhouse gases.

Most scientists agree that the Earth's atmosphere contained very little oxygen when the planet formed 4.5 billion years ago.

Over didn't know what the atmosphere contained, but Senexi activity had been high in the star system, concentrating on this world.

Everywhere on Earth, even in the hottest climates, the surrounding atmosphere contains at least some water.