History of Earth

 Through relative dating, a geologist finds a fossil that is approximately 10,000 years old. Which radioactive element would the geologist most likely use to accurately calculate the fossil’s age?

• gallium-67 with a half-life of 78 hours 
• carbon-14 with a half-life of 5,700 years 
• plutonium-238 with a half-life of 88 years
• iodine-129 with a half-life of 16 million years

Several dinosaur bones are discovered buried in volcanic ash. The type of dinosaur can best be identified by 

• knowing the location where the fossils were found
• establishing an inventory of bones collected. 
• comparing to characteristics of known dinosaurs
• knowing the absolute age of the fossils.

How are trilobite fossils helpful in understanding the distribution of living things throughout Earth’s history?

• Trilobites lived in all the ancient oceans and in varying depths of water. 
• Trilobites were found worldwide and are signature creatures of the Paleozoic Era. 
• The soft tissue of trilobites preserved well and began the expansion of biological diversity. 
• There were many different species of trilobites, and they existed in varying shapes and sizes. 

Geologists are conducting research in Hawaii. Which rock will be most abundant? 

• igneous
• metamorphic
• sedimentary
• none of the above

If a fault cuts through multiple layers of rock, which is most likely true? 

• An earthquake happened after the layers formed. 
• An earthquake happened before the layers formed. 
•  An earthquake happened at the same time the layers formed.
• The timing of an earthquake is unrelated to when the layers formed.

Through relative dating, the age of a rock was determined to be between 15,000 and 25,000 years old. How long should the half life be of the radioactive element used to date the rock layer? 

• five thousand years
• one million years
• five million years
• 1 billion years

Which statement below best explains why several fossils of sea organisms were discovered buried deep in an area of dry land? 

• The fossils changed locations
• The area had a shift in climate
• The land was once underwater
• A glacier once covered the area. 

An undisturbed rock column contains a fossil of a reptile species in the lowest rock layer, an index fossil that was present 1 million years ago in the middle rock layer, and a fossil of a clam species in the top rock layer. Which statement is most likely correct?

• The index fossil formed when a desert habitat made rock layers in the column. 
• There was a marine habitat over one million years ago that formed rock layers in the column. 
• There was a desert habitat before a marine habitat that formed the rock layers in the column. 
• There was a desert habitat more recently than one million years ago that formed rock layers in the column. 

Why are index fossils good clues for identifying when rocks were formed? 

• They are easy to form in rock. 
• They are difficult to form in rock. 
• They only existed during specific periods of time. 

A cliff of undisturbed rock layers has a layer of sandstone containing a reptile fossil above a limestone layer. The limestone layer is above a layer of shale. Which describes the most likely geologic history of the area?

• The area was first a marsh environment, then an ocean, and lastly a desert environment. 
• The area was first a desert environment, then a marsh, and lastly an ocean environment. 
• The area was first an ocean environment, then a marsh, and lastly a desert environment. 
• The area was first a desert environment, then an ocean, and lastly a marsh environment.