Answer:
(1) Humiliation by the Treaty of Versailles
War indemnity.
The provision for disarming Germany.
Saar coal mine to France for 15 years.
Polish corridor was given to Poland.
City of Danzing was made free.
(2) Growth of Fascism and Nazism
Mussolini (Italy) and Hitler (Germany) strongly glorified war and violence.
While West was fighting communism, Germany and Italy started massive militarization.
(3) Rise of Japan
Imperialism.
Rome-Berlin-Tokyo axis (1936).
(4) Neglect of minority interests
New countries like Poland, Czechoslovakia and Austria were formed after the First World War. While drawing boundaries the interests of minority groups in each of these countries were neglected.
(5) Military Alliance
Allies – Britain, France, USA, USSR and China vs Axis Powers – Germany, Italy and Japan
Leaders – Churchill (Britain), Roosevelt (USA), Stalin (USSR)
(6) Germany’s attack on Czechoslovakia
In-spite of the Munich Pact between Germany and Britain (1938), Germany re-attacked and sized Czechoslovakia.
(7) Immediate Cause : Germany’s invasion of Poland (1st September 1939)
Germany annexed Polished corridor and Danzig city. The sudden attack on Poland is known as Blitzkrieg (lightning war).
Brtiain and France declared war on Germany.