What’s the significance in the number 7 in history

The Seven Years War

Explanation:

Largely considered one of the first world wars involving many superpowers, the war ended in France losing all of its claims in the newly found continent of America, and Canada became a British commonwealth AND Spain received Florida and Louisiana. Not too sure what you meant by this question, so sorry if this doesn't help.

d) in the state of iowa

less available tax revenue

this basically means that when they get money from taxes wirth having a lower gdp they get less then what others have with a higher gdp