Asteroids are celestial rocky bodies that orbit the sun. It was Sir William Herschel who first coined the term âasteroidâ (Greek for star-like) in 1802. He thought that Ceres and Pallas, discovered in 1801 by Giuseppe Piazzi and Heinrich Olbers respectively, were too small and were remnants of a destroyed planet.
blood cell. n. Any of the cells contained in blood; an erythrocyte or leukocyte; a blood corpuscle. blood cell. n. (Physiology) any of the cells that circulate in the blood. See erythrocyte, leucocyte.
White blood cell. White blood cells (WBCs), also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as hematopoietic stem cells. Leukocytes are found throughout the body, including the blood and lymphatic system. All white blood cells have nuclei, which distinguishes them from the other blood cells, the anucleated red blood cells (RBCs) and platelets. Types of white blood cells can be classified in standard ways.