30.5 Exercise 3

Which of the following is the best way of explaining why the leaves on a given tree are green?

1. The molecules in the leaves absorb all visible light but strongly reflect green light.
2. The molecules in the leaves absorb green light and reflect other visible light.
3. The molecules are excited by external light sources, and their electrons emit green light when they are de-excited to a lower energy level within the molecules.
4. The molecules glow with a characteristic green energy in order to balance the absorption of energy due to light and heat from their surroundings.