Final answer:
The British supported imperialism to settle surplus population, create new markets for goods, and prevent civil war, highlighting economic and social motivations for empire expansion.
Step-by-step explanation:
The document from Cecil Rhodes provides insight into why the British supported imperialism. Rhodes believed that new lands needed to be acquired to help solve social problems in the United Kingdom, such as unemployment and the threat of civil unrest. According to the document, the British saw imperialism as a way to settle the surplus population, to create new markets for British goods, and to avoid potential civil war. These reasons underscore the economic and social motivations behind the British empire's expansion.