Monks and Friars both take vows of poverty.
The correct answer for the given question above would be the third option. The Song Dynasty as compared to the Tang Dynasty is that, the Song Dynasty was smaller than the Tang Dynasty, but lasted for a slightly longer period of time. The Song Dynasty didn't expand much, whereas, the Tang Dynasty expanded to modern borders. Hope this answer helps.
The main focus city of the Crusades was Jerusalem. The idea was that it was Christian territory, or at least should be Christian territory, and they always went to reconquer it. The fourth Crusade never made it to Jerusalem because they were busy sacking Constantinople which had a lot of troubles due to constant wars of the Byzantine Empire.
At the time of the arrival of Europeans, the indigenous population was estimated to be just below 40 million people. After the contact with European diseases it is said to be significantly reduced and estimates suggest that in 1650 this population could be around 8-9 million people. (this is just an estimate, but it's the best from all the offered answers).