Answer:
Darwin's main contribution to the theory of evolution was his theory of natural selection.
Explanation:
Natural selection is the phenomenon that some organisms from a particular population fit better into their environment, that is, are more likely to provide surviving offspring than less well-adapted organisms. The best adapted organisms will increasingly gain the upper hand within the population (survival of the fittest). It is thus one of the mechanisms of evolution. Mutations in, and recombinations of, the genetic material of the organisms cause the genetic variation in the population, allowing this selection.
Most Americans supported isolationism. They didn't want to engage in another European war. Although this agreement didn't include sending troops to Europe, it involved sending 50 destroyers to UK, so the amount of help was rather major.
The correct answer is D.
Roosevelt Corollary is seen as an addition to the Monroe Doctrine in which the US stated it would not interfere with the politics of the European nations if they did not interfere in the Western Hemisphere. The Roosevelt Corollary was presented to the Congress after the Venezuelan crisis and it states that US will intervene and mediate the conflicts between European and the nations of Latin America and enforce any claims of the European nations if they are legitimate.
1. Cyrus McCormick
2. Sewing Machine
3. Samuel Morse
4. Eli Whitney
5. Cotton Spindle
6. Cotton gin
7. Charles Goodyear
8. John Deere
9. Francis Lowell
