The National Security Resources Board was a United States government agency created by the National Security Act of 1947 whose purpose was to advise the President, in times of war, on how to mobilize natural resources, manpower, and the scientific establishment to meet the demands of the Department of Defense.

What was the purpose of the national resources planning board? Okie... think carefully first, then make a decision:
The relevant information to answer the above question is: The National Security Resources Board was a United States government agency created by the National Security Act of 1947 whose purpose was to advise the President, in times of war, on how to mobilize natural resources, manpower, and the scientific establishment to meet the demands of the Department of Defense. So, the answer is to advise the President , in times of war , on how to mobilize natural resources , manpower , and the scientific establishment to meet the demands of the Department of Defense.