Question

Why do fireflies glow at night?

• A. Fireflies contain an organic compound.
• B. Chemical reaction involves emission of visible light.
• C. Fireflies produce two chemicals which mix with each other and oxygen.
• D. All of the above.

Answer 1

Answer: (D)

All of the above.

Fireflies glow at night because of a chemical reaction taking place which involves emission of light. Actually fireflies store a protein (luciferin), which combines with oxygen ($O_2$) in the air (in the presence of an enzyme) to form a new substance (oxyluciferin) along with the evolution of energy in the form of light.

Hence, the correct option is $D$