1¿por que era tan importante el control de las aguas para las civilizaciones surgidas en torno a los ríos Tigris y Éufrates? 2¿Que consecuencias tenían las crecidas de los ríos?

Witch one is it soo it the the question b.a,b,c,d

Impressions of tropical swamp plants were observed on rocks in polar regions. the impressions were dark black imprints, which means the fossils are examples of ( 1 ) the fossils tell us that polar regions ( 2 ) ( 1 ) a. carbonization b. mineralization c. trace fossils ( 2 ) a. had tropical plants that can grow in ice b. might have had a diffierent climate in the past c. will have abundent vegitation

Can someone me with this plz? ! i'm putting 20 points on it!