The invention of the what has had the greatest impact on computers

What is the main idea of this excerpt? 1.1.3

Examine these two paintings that depict famous events from american history. the image on the left, painted in 1940, shows the signing of the u.s. constitution in 1787. the image on the right, painted in 1836, shows the american victory at the battle of yorktown in 1781.which of these paintings should be considered a secondary source?

Which of these events was a severe setback for the u.s. war effort in the pacific?