Final answer:
August Weismann proposed the Germ Plasm Theory, emphasizing that inheritance is transmitted through germ cells and is separate from any environmental influence or an individual's experiences.
Step-by-step explanation:
August Weismann proposed the Germ Plasm Theory, which is a biological theory that states that the cells in the reproductive organs carry a complete set of genetic information that is passed to the egg and sperm. This concept contrasted the belief of blending inheritance, where genetic material was thought to mix during reproduction. Weismann's theory was crucial in understanding heredity, as it emphasized that inheritance is transmitted through germ cells (eggs and sperm), which are not influenced by the external environment or the organisms’ experience.