Dopamine, norepinephrine, and acetylcholine are all hormones excreted by the endocrine glands hormones excreted by the endocrine glands. a. secretions of the exocrine glands secretions of the exocrine glands.
b. drugs used in the therapeutic treatment of memory disorders drugs used in the therapeutic treatment of memory disorders.
c. enzymes involved with the degradation of interneuron signals enzymes involved with the degradation of interneuron signals.
d. neurotransmitters that excite or inhibit a neural signal across a synapse

d. neurotransmitters that excite or inhibit a neural signal across a synapse

Explanation:

Neurotramniters are molecules that transmit chemical messages from nerve cells by traveling across the synapse to target cells. Some of the most important neurotransmitters include acetylcholine, norepinephrine, dopamine, gamma-aminobutyric acid (GABA), glutamate, histamine and serotonin. Norepinephrine is a neurotransmitter synthesized from dopamine which is involved in the regulation of stress response, sleep, and blood pressure. Norepinephrine, also known as noradrenaline, is an important neurotransmitter involved in stress response and exercise. Finally, acetylcholine is a neuromodulator of the autonomic nervous system involved in attention responses, memory and motivation.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.

yes

no

blue is scattered more than other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time.