Question

Each element has its own emission and absorption lines. What is the best explanation for this?

Each element has a specific number of protons and neutrons.
Each element has a distinct number of electrons.
Each element has a unique set of physical characteristics.
Each element has unique energy levels.

Answer 1

Answer: its d) each element has unique energy levels

Explanation: got it correct

Answer 2

D. Each element has unique energy levels.