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).
This was after the Wars, and people had started to get their lives back. Population increased drastically. There was a need of more food and supplies.
It's why the 50s were called the baby booming era.
Based on the fact that people were rounded up and executed, and then buried in killing fields, this is the Cambodian genocide.
<h3>What was the Cambodian genocide?</h3>
It was a period of time where the Khmer Rouge were the government of Cambodia and launched assaults against their own people.
They would round people up, shoot them, and then bury them in mass graves that came to be known as the Killing fields. Over a million people died during this period.
Find out more on the Cambodian genocide at brainly.com/question/10463598.
1. There were still new and didn't have money nor supplies
2. The Union army that was enforcing reconstruction might have been tolerant to low quality schooling or had not payed much attention to it