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.
The second one probably because of the law of conservation of mass where mass is not created or destroyed, so the mass has to be the same.
Chesapeake bay is an area that has suffered from overharvesting and eutrophication. Eutrophication is an enrichment of water by nutrients salts that causes structural changes in the ecosystem such as increased formation of algae and aquatic plants, depletion of fish species among other effects. The greatest source of nitrogen and phosphorus in a Chesapeake bay is agriculture
I believe it was The Continental Drift Theory , i could be wrong
