Albert Sabin came up with an oral polio vaccine in 1962
Answer:
The Inca road system formed a network known as the royal highway or qhapaq ñan, which became an invaluable part of the Inca empire, not only facilitating the movement of armies, people, and goods but also providing an important physical symbol of imperial control. Across plains, deserts, and mountains, the network connected settlements and administrative centres. Well-built and lasting, many roads included bridges, causeways, stairways, and also had small stations (chaskiwasi) and sometimes larger, more luxurious complexes (tambos) dotted along every 20 km or so, where travellers could spend the night and refresh.
Explanation:
Answer:
C. A British captain explored the Pacific Islands
Explanation:
The main factor that contributed to Britain establishing colonies in the Pacific islands is that "A British captain explored the Pacific Islands."
This is evident in the fact that a British explorer or navigator known as James Cook explored the uncharted territory covering the Pacific Islands from the area of New Zealand to Hawaii around 1768 to 1779. His exploration knowledge led the Europeans particularly Britain to establish colonies in the region.
The best answer is A.
Popular sovereignty was a doctrine under which the status of slavery could be determined by the settlers themselves. Although the doctrine won wide support as a means of avoiding conflict over the slavery issue, its meaning remained rather ambiguous since those who supported it disagreed as at what stage as territories developed should the decision be made.
A. Douglas, a main promoter of the doctrine, wanted the choice to be made at an early stage of settlement, while others felt that it should be made just before each territory achieved statehood. It was first proposed by vice president George Dallas in 1847 and popularized by Lewis Cass in 1848.
If a bill has passed in both the U.S. House of Representatives and the U.S. Senate and has been approved by the President, or if a presidential veto has been overridden, the bill becomes a law and is enforced by the government.
