What grade are you in (I’m asking this because on different grades they r different answers)
"To accommodate for lack of dependable rainfall" would be the best option as to why the ancient Chinese organized large groups of people to build and maintain irrigation systems, since when rainfall would not come for long periods of time, the crops would likely die without proper irrigation.
Calvinism is basically Protestantism, but since John Calvin played a huge role in Calvinism, it is named after him. The people who practiced Calvinism, often believed they were "chosen" by God to like on their life and do what they are told. They thought that God had picked them to make a perfect Christian community, as they had lived good and true lives so they were hand chosen by God himself. They trusted in the fact that if they did this and created a pure Christian community, while living a happy life with no sin, they would earn salvation from God.
90% is the percent of Jews.