Can you explain to be the definition of quantum theory?

Apossible explanation for a set of facts that can be tested by further investigation is called

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

Organelles are 1. responsible for producing power for the cell 2. tiny structures in the cell that carry out the cell's activities 3. responsible for digestion in the cell 4. found outside of the membrane