What is the difference between primary and secondary sources?
a. primary sources are always reliable, while a secondary source's reliability depends on its creator.
b. primary sources are firsthand accounts, while secondary sources are created after the fact.
c. primary sources are very old, while secondary sources are created recently.
d. primary sources are created by regular people, while secondary sources are the work of experts.

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.

an earnest tone.

because portia wants to know why brutus has been acting strange lately.