Which part of the electromagnetic spectrum have the highest level of photon energy

The energy carried by one photon is directly proportional to its

frequency. So the photon energy is greatest for the electromagnetic

waves with the highest frequency / shortest wavelengths.

That's why when you get past visible light and on up through ultraviolet,

X-rays, and gamma rays, the radiation becomes dangerous = = > each

photon carries enough energy to tear electrons away from their atoms,

ripping molecules apart and damaging cells.

The photon with the highest energy is a gamma-ray photon.