â¢ Medium-grained (1/16 mm to 2 mm) rocks are usually called sandstone. Medium-grained rocks can be composed of quartz grains, feldspar grains (arkose), or rock fragments and clay (graywacke). Sandstone (Photograph by Parvinder Sethi). Medium-sized grains in clastic sedimentary rocks form sandstone. This sample is a quartz sandstone.
Eukaryotes are those organisms in which the cell body contains a nucleus whereas prokaryotes are those organisms in which the cell body does not contain a nucleus. In amoeba, the reproduction is carried out under the instruction of the nucleus thus making it a eukaryote organism.
In prokaryotic cells, all 3 RNA classes are synthesized by a single polymerase. In eukaryotic cells there are 3 distinct classes of RNA polymerase, RNA polymerase (pol) I, II and III. Each polymerase is responsible for the synthesis of a different class of RNA.n prokaryotic cells, all 3 RNA classes are synthesized by a single polymerase. In eukaryotic cells there are 3 distinct classes of RNA polymerase, RNA polymerase (pol) I, II and III. Each polymerase is responsible for the synthesis of a different class of RNA.