they all include studying, either history or people, or nature. they all include observing something and studying it.
Answer:
hope you have a nice day ! :)
Explanation:
The Alliance System played an important role in leading to the First World War mainly because it divided the European powers into two rival military camps, the Triple Alliance and the Triple Entente by 1907. The rivalry between the two camps brought about the First World War.
I believe the answer is slavery.
• for love
• for religious beliefs
• want to have children
• to make a commitment to each other