Answer:
the reason for which something exists or is done, made, used.
Answer:
D. A signal is sent down an exon within a nerve cell
Explanation:
Rods and cones are similar in that they both release glutamate as the primary neurotransmitter. During signalling the rod and cone photoreceptors signal their absorption of photons via a decrease in the release of the neurotransmitter glutamate to bipolar cells at its axon terminal. Every rod and cone photoreceptor release the same neurotransmitter, glutamate.
