AP BIOLOGY

Detailed explanation-1: -Fossils are the remains or impressions of organisms, preserved in petrified molds or casts.

Detailed explanation-2: -Trace Fossils Trace fossils are marks left by an animal or plant that has made an impression. These fossils include nests, burrows, footprints or any other markings of the animal’s time on the earth. The structure of the animal or plant remains as a mineral form.

Detailed explanation-3: -Mold: Fossils formed when the sediment surrounding a buried organism hardens. When the organism decays, its impression is left in the rock and can be seen if the rock is broken open.

Detailed explanation-4: -We find molds where an animal or plant was buried in mud or soft soil and decayed away, leaving behind an impression of their bodies, leaves, or flowers. Casts are formed when these impressions are filled with other types of sediment that form rocks, which take the place of the animal or plant.

Detailed explanation-5: -Molds and casts form when the original skeletal material dissolves. The organism leaves behind an impression in the sediment called a mold. If that impression fills with new sediment, it creates a cast.