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.
The Senate is the branch of Congress in which each state is represented equally.
Answer:
This excerpt is from a <u>primary</u> source. The author of this excerpt is <u>Rebecca Maksel</u>. The events presented in this excerpt occurred in <u>1936</u>. The <u>main idea</u> of this excerpt is that Dorothea Lange's photos of Depression-era migrant workers helped expose their terrible living conditions.
Explanation:
