Final answer:
False. Social planners did not gain acceptance for hybrid grains and better sanitation methods through unplanned change among the peoples of underdeveloped societies.
Step-by-step explanation:
False, Social planners did not gain acceptance for hybrid grains and better sanitation methods through unplanned change among the peoples of underdeveloped societies. In fact, the acceptance of hybrid grains and better sanitation methods often required deliberate planning and implementation by social planners and organizations. They would introduce and promote these innovations through education, infrastructure development, and policy initiatives. Unplanned change may occur in societies, but it is not the primary method by which social planners gain acceptance for such innovations.