How did gorbachev reforms lead to the breakup of the soviet empire?

Gorbachev's policies of glasnost and perestroika lead to the collapse of the Soviet empire.

Glasnost (meaning openness) gave more rights to the media and individual citizens. This meant that citizens and the media could criticize the government, learn about other world events, etc. This was previously limited to Soviet citizens. Glasnost lead to increased questioning of the government and calls for immediate change.

Perestroika was focused on giving citizens more economic freedoms. Instead of the government planning out most of the economy, the citizens now had the ability to choose what they bought. This resulted in the fall of the communism in the Soviet Union and its satellite nations.

The answer is b biology