Joint stock companies:

a.
increased trade between the west indies and north america.
b.
established the columbian exchange.
c.
reduced investment fraud.
d.
allowed individuals to combine their money to invest.

the american rail road was the most influential and useful transportation system developed in the 1800's with steam locomotives and in the very late 1800's and early 1900's diesel electric locomotives being used to transport goods and people around the newly expanded united states!

b) race riots in several cities