Short answers, pulled from the story.
The Armia Krajowa numbered about 100,000 members when it was formed in February 1942. By early 1943 it had grown to approximately 200,000. At its peak in summer 1944, estimates of AK membership ranged from 300,000 to 500,000, and its total strength including allied groups such as the National Armed Forces was estimated at 650,000.
Witold Pilecki deliberately allowed himself to be captured in a Warsaw street roundup on the 19th of September 1940 and was sent to Auschwitz. Inside the camp he organized an underground resistance network called the Związek Organizacji Wojskowej (ZOW), which transmitted intelligence reports about the Holocaust to the Home Army beginning in November 1940. His reports became the principal source of Western Allied intelligence on Auschwitz-Birkenau.
The Polish resistance provided 43 percent of all intelligence reports received by British intelligence agencies from occupied Europe during World War II. Among its most significant contributions was the intelligence on German V-2 rockets, including some 50 kilograms of captured V-2 parts transported to Brindisi by a Royal Air Force Douglas Dakota and delivered to London in late July 1944.
Żegota, formally the Council for the Aid of the Jews, was founded in September 1942 by Zofia Kossak-Szczucka and Wanda Krahelska-Filipowicz. Poland was the only occupied country in Europe to maintain such a dedicated secret organization for protecting Jewish people. Żegota aided more than 50,000 Jews who survived the war, roughly half of Jewish survivors in Poland. Its best-known activist, Irena Sendler, saved 2,500 Jewish children by smuggling them out of the Warsaw Ghetto.
In March 1945, sixteen leaders of the Polish Underground State were lured to a meeting with Soviet General Ivan Serov under a warrant of safety, then arrested by the NKVD on the 27th and the 28th of March in Pruszków. They were taken to the Lubyanka prison in Moscow, subjected to months of interrogation and torture, and charged with fabricated accusations of collaborating with Nazi Germany at a staged show trial known as the Trial of the Sixteen.
Between the 1st of January 1941 and the 30th of June 1944, the Union of Armed Struggle and Home Army damaged or destroyed 6,930 locomotives, derailed 732 transports, damaged 19,058 railway wagons, blew up 38 railway bridges, and damaged or destroyed 4,326 army vehicles. Built-in sabotage faults were introduced into 92,000 artillery missiles and 70,000 condensers. Pre-planned assassinations of German personnel totaled 5,733.