Unit 7 Review

The diagram shows different layers of sedimentary rock. Each layer is labeled with a letter.

• The left part of Layer B is younger than the right part.

• The left part of Layer F is the same age as Layer M.

• Layer R is older than Layer M

• Layer I is older than Layer B

A teacher gave students this diagram of rock layers. The teacher directed the students to determine the relative age of each rock layer based only on the information presented in the diagram.

Which method can BEST be used by the students to determine the relative age of these layers?

• radiometric dating

• rock type evaluation

• the law of superposition

• principle of uniformitarianism

Certain fossils can be used to help determine the age of the rock layer in which the fossils are found. Which type of fossil is BEST to use when making this determination?

• marine mammal fossil

• swamp fern fossil

• trace fossil

• index fossil

Trilobites are extinct animals that lived in the oceans. Fossils of these animals can be found in dry areas such as Cincinnati. What does this indicate?

• Trilobites now live underground.

• Trilobites are the ancestors of jellyfish.

• Cincinnati was once covered by the ocean where trilobites lived.

• The environment changed, creating small saltwater lakes in Cincinnati.

What is the longest unit of time?

• Eon

• Era

• Period

• Epoch

What Era are we currently in?

• Paleozoic

• Mesozoic

• Cenozoic

• Triassic

Which Era was dominated by dinosaurs?

• Paleozoic

• Mesozoic

• Cenozoic

• Cambrian

Which era began with the early invertebrates, such as trilobites and brachiopods.

• Paleozoic

• Mesozoic

• Cenozoic

What type of rock do fossils form in?

• Igneous
• Sedimentary
• Metamorphic
• Classic

An event in time when large amounts of animals and plants die off

• geologic time
• precambrian
• period
• mass extinction