Question

Which grouping of light sources below share a common trait?
1. Bioluminescence, Incandescent light, Sunlight

2. Sunlight, Fluorescent light, Incandescent light

3. Phosphorescent light, Fluorescent light, Sunlight

4. Incandescent light, Phosphorescent light, Fluorescent light.

Answer 1

1. Bioluminescence, Incandescent light, Sunlight
^^^ light produced by heat or by chemical reaction

as opposed to Phosphorescent light / Fluorescent light
<< where light first needs to be absorbed ... and is later re-emitted