<span>Scientists choose where are units of time began and ended based on major changes in life forms at certain times</span>
Because there have been many invasions the correct answer would be C. The invasions would have brought many different ethnic groups into the area.
I think it's D. I'm not positive though.
Answer:
Wetlands.
Explanation:
An area of land that is covered with a shallow layer of water during some or all of the year.