Methylphenidate is a commonly prescribed psychostimulant and works by increasing the activity of the central nervous system. It produces such effects as increasing or maintaining alertness, combating fatigue, and improving attention. The short-term benefits and cost effectiveness of methylphenidate are well established.
(image copied from here). 1  Igneous Rocks: form by crystallizing melted material (magma). 2  They can form either on the surface (extrusive igneous rocks), or deep in the crust (intrusive or plutonic igneous rocks).
Rocks are classified by the way they form. Igneous rocks are those that form when magma cools and hardens. This process can occur on the Earth's surface or underground.The exact location of the formation of the rock determines the type of igneous rock it is. Interesting Igneous Rocks Facts:ocks are classified by the way they form. Igneous rocks are those that form when magma cools and hardens. This process can occur on the Earth's surface or underground. The exact location of the formation of the rock determines the type of igneous rock it is. Interesting Igneous Rocks Facts: