[Solved] The autonomic nervous system is: A) self-governing. B) part of the skeletal nervous system. C) part of the central nervous system. D) responsible for voluntary muscle action. Eosinophil: A type of white blood cell involved in allergic reactions and the defense against parasitic infections. Micrographs: Photographic or digital images taken using a microscope to magnify objects that are too small to be seen by the naked eye. Megakaryocyte: A large bone marrow cell responsible for the production of blood thrombocytes (platelets), which are necessary for blood clotting. Monocyte: A monocyte is a type of white blood cell part of the human body's immune system that fights off viruses, bacteria, and fungi; these cells can differentiate into macrophages and dendritic cells.