How did a warming climate 12,000 to 10,000 years ago impact the paleo indians living in the americas at the time?
a. paleo indians went to war with each other on a large scale due to scarce water resources
b. paleo indians relied less on hunting big animals and more on fishing and gathering food
c. paleo indians faced food shortages that resulted in a lower population
d. paleo indians lost land to rising sea level's

I think that the best answer is: b.paleo Indians relied less on hunting big animals and more on fishing and gathering food

let's look at the options: 

a. paleo Indians went to war with each other on a large scale due to scarce water resources
- This could be true if it was really hot, but this was not the case. Warming did not mean a really hot climate, but less harsh: so actually, there would be more, not less water resources.

b.paleo Indians relied less on hunting big animals and more on fishing and gathering food
- this is possible ! a warmer climate would mean that there would be more possibility to fish or gather food, which would mean that people didn't have to hunt - and they would not want to hunt big animals, as it's dangerous.

c.paleo Indians faced food shortages that resulted in a lower population
-no, a warmer climate would mean more, not less, food

d.paleo Indians lost land to rising sea level's
-no, they still had a lot of land.