Metamorphic grade is a general term for describing the relative temperature and pressure conditions under which metamorphic rocks form. As the temperature and/or pressure increases on a body of rock we say that the rock undergoes prograde metamorphism or that the grade of metamorphism increases.he original rock that has undergone metamorphism is called the protolith. Protolith can be any type of rock and sometimes the changes in texture and mineralogy are so dramatic that is difficult to distinguish what the protolith was. 1  Note that diagenesis and weathering are also a changes in form that occur in rocks.
Within the nephron (the functional unit of the kidneys), filtration occurs in the glomerolus. The filtered fluid is called filtrate. Reabsorption of filtrate occurs in a few places within the nephron, however, the majority of reabsorption takes place in the proximal convoluted tube.
Filtration is driven by the hydrostatic pressure of the blood, and causeswater and small molecules to be filtered, while blood cells and large molecules like proteins do not pass through the filter. Source [10]. In reabsorption & secretion, as the filtrate passes down the nephron most of it is reabsorbed into the blood.elieve it or not, the human kidney is capable of such a feat. The kidney is an amazing filtration device in that they can be used continuously for the duration of a human life without becoming clogged. If you re interested, learn more about the workings of the kidney below.