Many challenges and issues arose after countries gained independence from their former colonizers such as having a healthy economy, ensuring the national independence was permanent and creating a stable political system suitable for the rule of law.
The biggest issue was having a health economy because the duty of a country is providing for a good environment and catering for the well being of the citizens.
A reference group is a group that people compare themselves to—it provides a standard of measurement. In U.S. society, peer groups are common reference groups
Taking into account the statement above: "According to the reading on the course web pages, the earliest usage of stone tools began around _____ million years ago."