ANATOMY

Detailed explanation-1: -Fossils are the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers. Fossils also include any preserved trace of life that is typically more than 10 000 years old.

Detailed explanation-2: -The oldest known fossils, in fact, are cyanobacteria from Archaean rocks of western Australia, dated 3.5 billion years old. This may be somewhat surprising, since the oldest rocks are only a little older: 3.8 billion years old! Cyanobacteria are among the easiest microfossils to recognize.

Detailed explanation-3: -The fossil record certainly has gaps, mostly because the conditions required to create fossils have been rare ever since life began on Earth. A very small percentage of animals that have lived and died ever became fossils. Thus, many pieces of the puzzle are missing; some will never be found.

Detailed explanation-4: -Paleontological resources, or fossils, are any evidence of past life preserved in geologic context.