Which stratigraphic principle is most frequently used to determine relative age among different kinds of geologic events

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

In the late 1990s, brazil’s poor people protested about crowded cities land distribution mining permits industrial pollution

Hey, i was what is consisted in a sustainable city? like what unique designs they have, etc. for answering ; )