Light sources that are naturally existing in the environment.

Sources of light are made by humans.

It happens when certain chemicals in their bodies react to create light.

What type of source of light is the sun?

What should you apply to your skin to protect it from sunlight?

Andy stares at the sun to observe it.

Light exists in different colors.

Staring at computer screens for too long.

The sun is Earth's main source of light.

The sun gets its light from the moon.