What was the first killing center or extermination camp in poland

The first assassination city was the extermination camp of Chelmno, in Poland, where was the trial for the first occurrences of gas killings were performed. Chelmno started to kill whole extradition trains from November 1941 on. Then reached Belzec,  Sobibor, Auschwitz, Maïdanek, and Treblinka. The extermination camps performed a fundamental function in the Holocaust.

the answers is b.   environments.

first industrial revolution - the first wave of the industrial revolution lasted from the late 1700s to the mid-1800s. it industrialized the manufacture of textiles and began the move of production from homes to factories. steam power and the cotton gin played an important role in this period.