This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Which one of the listed statements best describes the process called chemotaxis? \nSelect and explain. \nA. Abnormal fusion of phagosomes to primary lysosomes, B. Attachment of chemicals to extracellular material to increase phagocytosis, C. Dilation of blood vessels by chemotherapeutic drugs, D. Movement of cells toward a certain site or source', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Chemotaxis is the unidirectional migration of cells toward a certain site or source.', 'role': 'assistant'}]