Recipe for Planet Earth

Ingredients:

• 1 part hydrosphere (the earth's water)
• 1 part lithosphere (the earth's rocks and minerals)
• 1 part atmosphere (the earth's air)

Directions:

To create the perfect biosphere (all parts of the earth that support plant, animal, and human life), mix ingredients carefully. The atmosphere accounts for the largest section of the biosphere. Gases from the air are found as far away as 600 miles (965 km) from Earth.