Answer:
The correct answer is D. The use of airplanes for mail transport.
Explanation:
Passenger transportation services began to expand through the mail business and at the same time they began to prosper in important markets.
Since the establishment of this kind of service, airplanes became faster, bigger, and they have had improvements in terms of fuel-efficient. However, the technological improvements in the airline industry have decreased, but there are still some innovations that could be applied.
Passengers prefer the use of airplanes because they can travel long distances in less time and because the airlines usually offer competitive prices.
Because the black community wanted to show that they were equal to the white community. So they sat in white only cafés refusing to move until they got their rights and freedom.
A. Made Egypt Wealthy through trade
Many Indians and colonist died