Who were the first group of people to arrive in Guyana​

Answer :

Arawak, Carib, and possibly Warao

The first human inhabitants of Guyana probably entered the highlands during the 1st millennium bce. Among the earliest settlers were groups of Arawak, Carib, and possibly Warao (Warrau). The early communities practiced shifting agriculture supplemented by hunting.

https://www.britannica.com/place/Guyana/History

The answer here is :

The study of buying and selling decisions.

Explanation:

Most interactions in a free-market economy  are about buying and selling products and services for a profit. Economics studies the processes related to buying and selling and what are the best ways to do it. This definition includes the other actions. Economics is not only about business management but also about goverment macroeconomic and fiscal decisions.