Answer:
A. Airplane
Explanation:
Around 1918, Air delivery, became the new mode of transportation for mail, as it rendered railroad services unnecessary. During this period, the Post Office moved on the airplane bandwagon early, there by, offering air mail service in the early 1900s.
Hence, the 1900's technological invention which allowed the U.S. postal service to deliver the mail considerably faster than previous methods is AIRPLANE.
There were several reasons why Stalin started a policy of rapid industrialisation in the late 1920s, but the main reason is that he saw that Russia was falling behind the western world.
The likely effect of such trail lines that were left by pioneers migrating to the west were that people who moved there afterrwards were able to derive information regarding where it was relatively safe and where territory has been charted and mapped before. This enabled a little certainty in areas of great danger.
b and after the building of the canals and the type of floods the rivers had, the crops were abundant, so c is the consequence and there was a surplus of food. Not everybody needed to work in the fields. Some devoted to other jobs like soldiers, rulers, etc. And so they went to live in cities or villages. But in order to distribute the products a strong ruler (it could be called king, priests, army so the state was born) was necessary. .
