Isaac Is in a Room That Is Almost Completely Dark

Multiple Choice

Isaac is in a room that is almost completely dark. He notices while lying in bed that if he tries to focus on the faint little red light on the fire detector, it seems to disappear. When he asks his mother why this happens, she explains that the eye receptors that understand colour do not function well in very dim light. To which receptors is she referring?

A) rods
B) cones
C) cylinders
D) ganglia
E) bipolar cells