Concept:Lamarck proposed an early theory of evolution through the inheritance of acquired characteristics.Explanation:Jean-Baptiste Lamarck is directly credited with developing an early evolutionary theory.His work on how organisms adapt to their environment contributed to later evolutionary thought.The other scientists worked on different subjects: Mendel on genetics, Morgan on chromosomes, and Pasteur on microbiology.So Lamarck is the correct choice.Answer:A. Lamarck