Answer :
When they began to stay in the some area for along time, they began to call that 'home'. They didn't like when someone invades there 'home'.
Now lets use this analogy in real life. When a large population settles in a certain area for a long time, they begin to consider that area as there, therefore it was there defined territory.
So your answer would be The first option.
Hope I helped. :)
Answer:
Civilizations began to develop a defined territory.
Explanation:
Once people began to live in one place, civilization as we know it today began to develop. People began to build permanent settlements. These settlements also allowed people to begin to feel that they belonged to a certain geographic location. This caused the territories of a particular civilization to have definite boundaries.