EOG Review Questions

What can be concluded about the age of fossils in undisturbed rock layers?

• The top layer has the oldest fossils.
• The bottom layer has the oldest fossils.
• The top layer has the oldest and youngest fossils.
• The layers cannot be used to determine the age of fossils

The picture shows the fossilized tooth of an extinct shark called a Megalodon. Which evidence can scientists most likely gain from studying the fossilized tooth?

• the different types of prey eaten by the shark
• the differences from teeth of living sharks
• the events that led to how the shark died
• the color of the skin of the shark

Radioactive dating is used to study which element in igneous and metamorphic rocks?

• Carbon
• Krypton
• Uranium
• Hydrogen

Scientists find dinosaur fossils in the bottom rock layers of a cliff and mammal fossils in the middle rock layer of the cliff. Which could best be concluded from this evidence?

• Dinosaurs ate plants.
• Dinosaurs were eaten by the mammals.
• Dinosaurs lived on Earth before the mammals.
• Dinosaurs and mammals lived at the same time.

Which material from an archaeological dig is least likely to be studied using the radioactive isotope carbon-14, which is found only in living (and formerly living) organisms (plants and animals?

• bone fragment of fish

• granite cutting tool

• tooth of a mammal

• wooden tool handle

Which statement is most accurate regarding fossils?

• Fossils found in upper layers of a rock section are generally younger than those in lower layers

• Fossils are an indicator of ancient environmental conditions

• Absolute ages of all fossils are determined by using carbon dating technology

• Marine organisms with hard body parts rarely become fossils

Which best describes the criteria necessary for a fossil to be used as an index fossil?

• The fossil must be from a mammal.
• The fossil must be found both in rock layers on the land and in rock layers under the oceans.
• The fossil must be found in areas on Earth and must be from an organism that lived for a relatively short time span.
• The fossil must be found in at least three different types of sedimentary rock layers and at least two different types of igneous rock layers.

Scientists have discovered a fossil skeleton of a whale-like creature that lived in the early Eocene epoch. The skeleton shows an organism with large fore and hind limbs with distinct toes.
Fossil skeletons of closely related species from later periods show organisms lacking hind limbs. 
Which conclusion does this observation best support?

• Ancestors of whales may once have been able to walk
• Ancestors of whales had fewer bones than modern whale
• Whales and their ancestors have always been ocean dwellers
• Whales and their ancestors have always been the largest living animals

The diagram shows the front limbs of four different members of the horse family, based on the fossil record. They are arranged from the oldest to the most recent.
Which best describes how the front limbs of horses have changed over time

• They have gained additional toes
• The bones have become stronger
• The toes have reduced in number
• The bones have become shorter

Which best explains the significance of the trilobite as an index fossil?

• They were the first fossils to be discovered
• They are fossils that represent many different life-forms
• They were the only fossils found outside the United States
• They are fossils that indicate a certain era in geologic time