A lymphocyte is a type of white blood cell. White blood cells are part of your immune system and help your body fight off diseases, including infections and cancer. There are two main types of lymphocytes â B cells and T cells. B cells make antibodies that attack bacteria and toxins in the body.
- Mud, sand, and volcanic ash can make sedimentary rocks. bones leaves, stems, and other remains of living things. - Geologists classify metamorphic rocks according to the arrangement of the grains that make up the rock. - Metamorphic that have their grains arranged in parallel layers or bands are said to be foliated.
The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material.Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock.edimentary. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock.