World War II On September 1, 1939, Germany invaded Poland. On September 3 France and England demanded that Germany withdraw its troops. When Germany refused England and France declared war on Germany. Within a week Great Britian was joined in the war by Canada, Australia, New Zealand, the Union of South Africa, and India. Ireland was the only member of the British Commonwealth to keep out of the war. The start of the war climaxed a series of …showed first 75 words of 3269 total…

…showed last 75 words of 3269 total…Automatic methods and machinery replaced costly handwork in countless operations. Machines were developed to squeeze and mold metal like putty. New alloys and plastics were developed. Medicine and surgery made great advances. Penicillin might not have been produced for a generation in normal times. War insecticides such as DDT began a new age in controlling dangerous pests and disease carriers. The dangers posed by the use of pesticides would not be recognized for several years.