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 . The fossils tell us that polar regions .

the fossils are examples of... mineralization

The fossils tell us that polar regions... formed a supercontinent that divided and slowly drifted to polar regions

Explanation:

Mineralization is a type of fossilization where rich-mineralized water fills the pores of the dead tissues for a long time. Subsequently, when this water is evaporated, the excess of minerals is deposited on the tissues, thereby mineralizing organic tissues.

Fossils enable us to understand more accurately past climatic conditions from regions where these fossils were found. For example, the discovery of plant fossils closely related to tropical species in polar regions suggests that these regions were once a part of a super landmass known as Pangea that divided and drifted a long time ago (millions of years ago).

layer 3 is younger than layer 6.