Why do you think that the system of using indentured servants for labor eventually ended in the colonial period, yet the use of enslaved persons for labor continued for many years?

Free Labor

Explanation:

The stopped using the indentured servents because indentured servents were just working to pay off their debt becuase the person they were working for payed for that indentured servents way to come to America.  Once they paid off their debt they were free to go about their life and it didnt matter what color or race someone was.  They started using enslaved people because they werent paying off a debt and they could keep them working for as long as the person lived.  In Africa tribes were attacking other tribes and selling those they captured into slavery.  It was mostly the Spanish (from Spain) that bought them and then took them.  They were taking them mainly to Central America to work in the fields but about 15% of those the Spanish bought came to America.  Plantation owners saw that they could buy slaves and force them to work with out them leaving or paying them.  The plantation owners saw this as good for business.  There were also other races that were used as slaves in America such as the Irish and some whites, however the main race was African.

they wanted the u.s. to fight on the side of the central powers.

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.