Resonance occurs when one vibrating object transfers energy to a second object causing it to vibrate. The energy transfer is most efficient when, compared to the first object, the second object has the same natural 1)amplitude 2)speed

3)wavelength 4)frequency

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

frequency or wavelenth of em radiation in a vacuum

the rearrangement of particles in a physical change. hope this