an improvement in diet of the people in Europe.
Answer:
Stars
Explanation:
Sailors would either mark down notes of how many Nauts they have traveled which is how you measure sea distance then at night time they would follow the Nothern Star to find their way home. Thats why on most compasses there is a star on it also it is known that most people thought you would sail off the side of the earth because they believed it was all flat until someone found out that the earth was a Sphere it was an Astronomer as well.
General George McClellan was running against Abraham Lincoln in the 1864 presidential election as the Democratic nominee.
Britain and France declared war on Germany because it invaded Poland in 1939.