Final answer:
During April 1940 to September 1940, the Western Front included Germany and its allies like Italy. Germany launched a westward offensive, overrunning various countries and advancing into France.
Step-by-step explanation:
During the period of April 1940 to September 1940, the Western Front consisted of Germany and its allies, such as Italy. This was the time when Germany launched their westward offensive, overrunning countries like the Netherlands, Belgium, and Luxembourg, and advancing into France. The Western Front during this period saw intense fighting and significant territorial gains for the German forces.