What is an intrusion in geological terms?

• A) A type of fault

• B) A younger rock cutting through older rock

• C) A horizontal layer of sediment

Fill in the blank: The half-life of a radioactive isotope is the time it takes for half of the original atoms to ____.

• Double

• Decay

• Stabilize

• React

What happens to the amount of C-14 every 5,700 years?

• It doubles.

• It decreases by half.

• It remains the same.

• It increases by half.

How do scientists believe the Moon formed?

• From a collision impact between a Mars-sized protoplanet, Theia, and Earth

• From a piece of the Sun

• From a large asteroid

• From a volcanic eruption on Earth

List the eras of the Phanerozoic in order from oldest to youngest.

• Paleozoic, Mesozoic, Cenozoic

• Mesozoic, Paleozoic, Cenozoic

• Cenozoic, Mesozoic, Paleozoic

• Paleozoic, Cenozoic, Mesozoic

Fill in the blank: The Phanerozoic is divided into three eras: Paleozoic, Mesozoic, and ____.

• Cenozoic

• Proterozoic

• Archeon

• Hadean

Fill in the blank: The groups under the Time Distribution of Fossils with four or more index fossils include Brachiopods, Trilobites, and ____.

• A) Vertebrates

• B) Sponges

• C) Stromatolites

• D) Ancyrocrinus

Fill in the blank: The Precambrian Eon includes the eons Hadean, Archean, and ____.

• Proterozoic

• Paleozoic

• Mesozoic

• Cenozoic

Fill in the blank: The Phanerozoic Eras in order from oldest to youngest are Paleozoic, Mesozoic, and ____.

• Cenozoic

• Proterozoic

• Archeon

• Hadean

Complete the sentence: The formation of the Moon occurred approximately ____.

• 4.5 bya

• 2.4 bya

• 1.3 bya

• 542 mya