What is one way african americans served the union’s war effort?
a. they engaged in combat.
b. they protested against slavery.
c. they supported freedom and went to canada.
d. they staged demonstrations to end the war.

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding.i