Short answers, pulled from the story.
The codebreaking work was carried out at the Polish General Staff's Cipher Bureau in Warsaw by Marian Rejewski, Henryk Zygalski and Jerzy Różycki. On the 25th of July 1939, Poland shared its results with France and Britain at Pyry in the Kabaty Woods south of Warsaw, just five weeks before the war began.
A total of 145 Polish pilots defended British skies, 89 of them in four Polish squadrons and more than 50 in British squadrons. No. 303 Squadron, named for Tadeusz Kościuszko, claimed 126 kills, the highest total of any fighter squadron in the battle.
German-occupied Poland was the only European territory where helping a Jew meant execution for the helper and their whole family, yet Poland was also the only occupied country to create an organization built specifically to aid Jews. Żegota supplied food, shelter, medical care, money and false documents, funded mainly by the Polish Government-in-Exile in Great Britain.
Nazi Germany invaded Poland on Friday the 1st of September 1939, and the Soviet Union invaded from the east on the 17th of September under the Molotov-Ribbentrop Pact's secret protocol. German and Soviet forces held all of Poland by the 6th of October 1939.
Poland fielded the fourth largest Allied fighting force in Europe during World War II, ranking behind only the Soviet Union, the United States and Britain.
General Władysław Anders commanded the 75,000-strong army formed in the USSR in 1941 after Stalin agreed to release Polish citizens. The force was transferred to Iran in 1942 and joined the British Eighth Army in the Middle East as the Polish II Corps.