Over time, many trading posts established along the frontier

a. slowed expansion into the west.

b. were captured by american indians.

c. grew into towns and cities.

d. were abandoned when explorers returned east.

The correct answer is C) grew into towns and cities.

Over time, many tradeposts established along the frontier grew into towns and cities.

A trading post was a trading center where people came by to trade their goods. For instance, during the fur trade, the Hudson Bay Company established some trade posts in the Hudson Bay where many people did their trade activities. Other people and business started to establish around these trading post due to the number of traders and activities in those places. Over time, many tradeposts established along the frontier grew into towns and cities.

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories

just finished this it is b. centrifugal force