The natural greenhouse effect is nature’s way of keeping Earth warm.

Heat is transferred around the globe by wind and ocean currents.

Earth spins on its axis once every 24 hours, giving us the seasons.

Incoming energy from the sun is distributed evenly over Earth.

The most direct rays of the sun are those that hit Earth near the equator.

The greater share of solar energy is absorbed by the atmosphere.

The ozone layer is part of the troposphere.

The troposphere is the lowest layer of the atmosphere.

Oxygen is the most plentiful gas in the atmosphere.