Final answer:
Jean-Baptiste Lamarck first believed that acquired traits were inheritable.
Step-by-step explanation:
The correct answer is Lamarck. Jean-Baptiste Lamarck was a French biologist who proposed the theory of inheritance of acquired characteristics. He believed that traits acquired by an organism during its lifetime could be passed down to its offspring. For example, he suggested that giraffes' long necks were the result of their ancestors stretching their necks to reach high leaves, and that this elongation of the neck was then passed on to future generations. However, Lamarck's theory has been largely discredited in modern biology.
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