Serotonin and n<span>orepinephrine.
Serotonin decreases appetite by activating </span>5-HT2C receptors<span> on dopamine-producing cells which will cause dopamine release to stop. Dopamine is responsible for the increase of appetite, therefore, serotonin decreases appetite.
Norepinephrine by increasing the production of glucose it also causes the body to feel satiety and, therefore, decreases the appetite.</span>
The correct answer is a law
Laws explain what occurs, not why it occurs. This is a law because it states that a limp stalk of celery will become crisp if put into ice water. There is no explanation why or how it occurs, only that it will happen.
Mutuaism
because they both benift from each other
They always increase in numbers