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.
In many formations of strata there are repeating patterns. For example, clay layers alternate with sandstone layers; or carbonate layers alternate with shales. This is usually caused by repeating cycles of climate. In warmer times the sea rises, and carbonate rocks are deposited in shallow subtropical seas.