Final answer:
Rods are the receptor cells in the retina responsible for night vision and perception of brightness. They are more sensitive than cones and do not yield color information. There are about 120 million rods in the human retina.
Step-by-step explanation:
The receptor cells in the retina responsible for night vision and perception of brightness are rods. Rods are more sensitive than cones and are solely responsible for peripheral vision and vision in very dark environments. They do not yield color information, but they enable us to discern shades of gray. There are about 120 million rods in the human retina.