Malaria is caused by a parasite called Plasmodium, which is  transmitted via the bites of infected mosquitoes. In the human  body, the parasites multiply in the liver, and t â¦ hen infect red  blood cells. Usually, people get malaria by being bitten by an  infective female Anopheles mosquito.   *Ninety percent of malaria-related deaths occur in Africa. Malaria is commonly associated with poverty, but is also a cause of poverty.   *Malaria is one of the most common infectious diseases and an enormous public health problem.
metamorphic rock. (petrology). A rock formed from preexisting solid rocks by mineralogical, structural, and chemical changes, in response to extreme changes in temperature, pressure, and shearing stress.
Quartzite, a form of metamorphic rock, from the Museum of Geology at University of Tartu collection. Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means change in form. The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 Â°C) and pressure (1500 bars), causing profound physical and/or chemical change. The protolith may be a sedimentary rock, an igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and are classified by texture and by chemical and mineral assemblage (metamorphic facies).