Stressor due it comes from an external condition or event.
<span>1.
</span>Cones perceive
light in color while rods perceive light in black and white.
<span>2.
</span>Rods can perceive dim light, unlike cones. The rods are located at the edges of the eyes. This is why it easier to perceive an image in the dark through
the corner of the eyes.
<span>3.
</span>The discs that compose the cones are usually
partially open to the surrounding vitreous
fluid while those of the rods are closed.
After my research the answer is that they are forms of electromagnetic radiation as far as I know.
