Problem:
The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the Photosynthetically Active Radiation (PAR) range (the wavelength of light used for normal photosynthesis)?
Alternatively is there something special about photons with those energy levels that are leading to stabilizing selection in multiple species as diverse as humans and plants?
Describe something about the energy of photons and justify your answer.