1. Natural light, which produces heat and color, comes from the radiation given off by the sun. It is then filtered through the Earth's atmosphere and absorbed by plants, while Artificial light sources can consist of a filament that uses electricity or halogen gas to glow, or an electronic device that emits light.

2. The importance of sunlight to us is the Vitamin D. The sun's UV rays help your body make this nutrient, which is important for your bones, blood cells, and immune system. It also helps you take in and use certain minerals, like calcium and phosphorus.