The answer is the endogenous opiate.
The human body naturally produces its own opiates like substances and uses them as neurotransmitters. These substances include endorphins, enkephalins, and dynorphin, often collectively known as endogenous opioids. Endogenous opioids modulate our reactions to painful stimuli.
Answer:
All of the above
Explanation:
In letter A, B, and C; in different physical situation the molecule of water behave and put in charge with its peculiar polarity. Remember that is part its quite simple and molecular structure.
Water is "dipolar", because there is an uneven distribution of electron density. Water has a partial negative charge (Delta-) near the oxygen atom due the unshared pairs of electrons, and partial positive charges (Delta-) near the hydrogen atoms.