<prompt> Which one of the listed statements best describes the process called chemotaxis?Abnormal fusion of phagosomes to primary lysosomesAttachment of chemicals to extracellular material to increase phagocytosisDilation of blood vessels by chemotherapeutic drugsMovement of cells toward a certain site or source  <response>: Chemotaxis is the unidirectional migration of cells toward a certain site or source. 