Final answer:
The Chinese Communist Party's response to the Japanese occupation helped them win the revolution by accumulating supporters and supplies and gaining popular support through promises of land and wealth redistribution.
Step-by-step explanation:
During the Japanese occupation, the Chinese Communist Party (CCP) responded by accumulating supporters and supplies in the northwestern Shaanxi Province, while the Nationalists were focused on survival. Mao Zedong, the leader of the CCP, capitalized on the outrage caused by the Nationalists' failure to prevent the invasion and their scorched-earth retreat. Mao built a large force from local peasantry and gained popular support by promising equal distribution of land and wealth, which appealed to the majority of landless and poor farmers in China. As a result, by the end of World War Two, the CCP had gained significant strength and support, ultimately leading to their victory in the revolution.