Development of tolerance. Over time, the brain adapts in a way that actually makes the sought-after substance or activity less pleasurable. In nature, rewards usually come only with time and effort. Addictive drugs and behaviors provide a shortcut, flooding the brain with dopamine and other neurotransmitters.
There are two types of metamorphism: contact metamorphism and regional metamorphism. Contact metamorphism is a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma.This is an easy name to recall if you remember that these rocks change by actually coming in contact with something very hot, like magma.egional metamorphism is a type of metamorphism where rock minerals and texture are changed by heat and pressure over a wide area or region. Contact and regional metamorphism differ in both the area and pressure involved.
The way that they form. Non-foliated metamorphic rocks form at low pressures but high temperatures, while foliated metamorphic rocks form at high pressures. Most non-foliated metamorphic rocks are generally formed by contact metamorphism and are termed âHornfelsâ. There are a few metamorphic rocks that form under pressure with little obvious foliation, such as marble or quartzite, however these are generally mono-mineralic rocks.