Why do you think the governments of the united states and other countries encouraged people on the home front to organize programs for such activities as scrap collection and victory gardens?

Victory Gardens were a way of reducing American food consumption so that the country's agricultural base could focus on producing long-lasting, nutritious foods which would go to the soldiers fighting in Europe and the Pacific. Scrap collections were organized to recycle metal either for use in the creation of weapons like tanks and planes, or for reuse in the economy to avoid sucking up valuable military resources needed to defeat the Axis.
Hope that I helped!