Acetylcholine (ach) affects muscle action, learning, and memory. endorphins are natural opiates released in response to pain and exercise. drugs and other chemicals affect brain chemistry at synapses. agonists increase a neurotransmitter's action, and may do so in various ways. antagonists decrease a neurotransmitter's action by blocking production or release.

eukarya because is is like alche and b is bacteria and d is animals

explanation:

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.