In June 1987, Reagan challenged Soviet leader Mikhail Gorbachev to "tear down" the Berlin wall. two years later, the wall came down, then the enslaved nations of the Soviet empire gradually broke free, and the Soviet union collapsed.
Was involved in World War II.
It would be the development in agricultural knowledge/technology
Development in agriculture enable hunter/gatherer society to shift their behavior. Before this, they had to keep moving from one place to another in order to seek food to live.
After the development in agricultural knowledge/technology, the society now can stay in one exact place for a long period of time and relied on agricultural product as their main source food.
After living in one same place for a long time, the needs to build things to accommodate their living start to arise. They start to built several things and repeat the process every year. In the end, large cities were developed from the initially small hunter/gatherer society.
Answer: Cad a churieann Tocqueville i bhfréamh mhíshuaimhneas agus suaimhneas nah Meiriceánaigh
Explanation: