Who was the first african american billionaire in the united states?.

Robert L. Johnson

Explanation:

c. troops marched forward in close formation against newer, more accurate weapons

the right answer is the third one: turnpikes went short distances to connect markets. turnpikes, also known as toll roads, were very important for trade and transportation (of people, goods and products) in the 19th century, coinciding with the expansion towards the west. they contributed significantly to the economic development of the united states.