What unit of light stimulates photoreceptor cells in the retina?

Photons

Explanation:

The retina is a thin layer (membrane) in the eye that receives light through photoreceptor cells that convert this light into chemical and nervous signals transported to the brain's visual center.

The photoreceptors in the retina are known as rods and cones. Rods detect motion and sare responsible for black and white vision, they are present in the macula. Cones on the other and, are responsible for central and color vision. These photoreceptors absorb photons that trigger the membrane's potential of the cells.

I hope you find this information useful and interesting! Good luck!

answer; both surfaces of the membrane are nonpermeable