B because the temperature goes up then the birds would move to the south were it is cooler.
I think the anser is d that what i think Is
Disease, competition, and predation.
Make/produce and secrete hormones
<em><u>hope</u></em><em><u> </u></em><em><u>it</u></em><em><u> </u></em><em><u>will help uh</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em>