Which sources would preserve the soft tissues of an early mammal? Check all that apply.

amber in Russia

frozen soil in the Arctic

shale in Virginia

sandstone in the Badlands

foraminifera in the ocean

ice sheets in Greenland

Soft tissues of early mammals would preserve under the following conditions:

Amber in Russia Frozen soil in the Arctic Ice sheets in Greenland

The three possibilities shares a characteristic, which is the impossibility of microbes to act upon the organic compounds soft tissues are made of as they would under normal conditions. However, couple of years ago, paleontologist discovered a small mammal with preserved fur and internal organs (soft tissues), unearthed from 125-million-year-old rocks in central Spain, which could open the possibility for "sandstone in the Badlands" to be a correct answer too, but the fact which discard this presumption is that Badlands oldest sandstone are 65 to 75 myo (Cretaceous Period), not fitting in the period in which the small mammal was found in Spain.

amber in Russia

frozen soil in the Arctic

ice sheets in Greenland