Unit 7 Test Review

Unit 7 Test Review Ms Grant

A. Trace fossils take less time to form. B. Body fossils require soft sediment to form. C. An organism is more likely to live on soft sediment where trace fossils form. D. A single animal can leave thousands of traces in its lifetime but will leave only one body when it dies. Trace fossils are much more common than body fossils. Which of the following best explains why trace fossils are more common?

AND THE ANSWER IS…………… D. A single animal can leave thousands of traces in its lifetime but will only leave one body when it dies

What materials does radiometric dating use to determine the age of objects? A. fossils B. isotopes C. tree rings D. rock layers

AND THE ANSWER IS…………… B. isotopes

An igneous intrusion cuts through three layers of sedimentary rock. Which rock is the youngest? A. the igneous intrusion B. the top layer of sedimentary rock C. the middle layer of sedimentary rock D. the bottom layer of sedimentary rock

AND THE ANSWER IS…………… A. the igneous intrusion

What is the law of superposition? A. Igneous rock is older than nearby sedimentary rock, which is older than nearby metamorphic rock. B. A sedimentary rock layer in its original position is older than the layers above it and younger than the layers below it. C. Metamorphic rock is older than nearby sedimentary rock because sedimentary rock is deposited before metamorphic rock forms. D. The exact age of a sedimentary rock layer can be found using the layers above and below it, even if the layers are not in their original positions.

AND THE ANSWER IS…………… B. A sedimentary rock layer in its original position is older than the layers above it and younger than the layers below it.

Earth’s surface features slowly change over time. For example, sharp, jagged mountain ranges become lower and more rounded over time. What factor/s is responsible for this change in their shape? A. weathering and erosion B. deposition C. movement of continents D. collisions between continental plates

AND THE ANSWER IS…………… A. weathering and erosion

Chase wants to determine a more accurate age of a shell that is known to be between 10,000 and 30,000 years old. Which method would be most useful for finding a more precise age of the shell? A. radiocarbon dating B. uranium-lead dating C. potassium-argon dating D. relative dating

AND THE ANSWER IS…………… A. radiocarbon dating

Radiocarbon dating has a shorter useful time range than potassium-argon dating. Which statement bestexplains why? A. Carbon-14 is a common component of living things. B. Carbon-14 is not a common component of minerals. C. Carbon-14 has a longer half-life than potassium-40. D. Carbon-14 has a shorter half-life than potassium-40.

AND THE ANSWER IS…………… D. Carbon-14 has a shorter half-life than potassium-40

Each radiometric dating method is useful for a specific time range. Which method has the most useful time range of 100,000 to a few billion years old? A. relative dating B. radiocarbon dating C. uranium-lead dating D. potassium-argon dating

AND THE ANSWER IS…………… D. potassium-argon dating

A geologist is studying three layers of sedimentary rock in an area. The layers have not shifted from their original positions. The geologist records the relative ages of the rocks. The bottom layer is listed as the oldest. The top layer is listed as the youngest. What did the geologist use to determine the relative ages of the rocks? A. mineral content B. radioactive decay C. the law of superposition D. the principle of unconformity

AND THE ANSWER IS…………… C. the law of superposition

Which of the following methods is most likely to be used to determine the absolute age of animal bones that are less than 45,000 years old? A. radiocarbon dating B. potassium-argon dating C. uranium-lead dating D. relative dating

AND THE ANSWER IS…………… A. radiocarbon dating

Jun makes a poster to explain how the law of superposition applies to rock layers. He explained the ages of the top three layers. He still needs to explain the age of layer 1. His diagram is shown below. How should he explain the age of layer 1? A. It is the youngest layer because it is protected by the other layers. B. It is the oldest layer because it was deposited before the other layers. C. It is older than layer 2 because it is thicker and has been worn away the least. D. It is three times younger than layer 4 because it is three layers below layer 4.

AND THE ANSWER IS…………… B. It is the oldest layer because it was deposited before the other layers.

Layers of rock are not always found in uniform layers. They may be cut by faults. Melted rock may be pushed into the layers, where it becomes solid. The diagram shows rock layers that are cut by a fault and two bodies of rock (rock 1 and rock 2). What are the relative ages of the features in order of oldest to youngest? A. fault, rock 1, rock 2, layer 1 B. layer 1, rock 2, rock 1, fault C. rock 2, layer 1, rock 1, fault D. fault, rock 2, layer 1, rock 1

AND THE ANSWER IS…………… B. layer 1, rock 2, rock 1, fault

The diagram below shows one kind of radioactive decay that is used for dating. Which statement best describes what information is needed to determine the age of a rock sample using this type of dating method? A. the exact mass of uranium-238 in the sample B. the amount of lead-206 present in the sample C. the energy being released by the uranium-238 D. the relative amounts of uranium-238 and lead-206

AND THE ANSWER IS…………… D. the relative amounts of uranium-238 and lead-206

During most of Florida’s geologic history, the state was covered by the ocean. Today, the land surface of Florida is covered mostly by sediment and sedimentary rock. If you were to analyze the composition of Florida’s sedimentary rocks, which type of fossil would you leastlikely find? A. fossils of seashells B. fossils of fish bones C. fossils of palm fronds D. fossils of marine organisms

AND THE ANSWER IS…………… C. fossils of palm fronds

Scientists from three parts of Florida are comparing the rock layers in their areas. They want to arrange the layers according to their relative ages. The diagram shows the rock layers from each area. Which area has the youngest top layer compared to the other areas? A. area 1 C. area 3 B. area 2 D. The ages of the top layers are all the same.

AND THE ANSWER IS…………… A. area 1

Scientists have discovered dinosaur fossils that have evidence of feathers. Some scientists think the feathers might have kept the dinosaurs warm. If so, in what type of environment did these dinosaurs probably live? A. hot desert B. tropical rain forest C. region near the equator D. area with cold seasonal temperatures

AND THE ANSWER IS…………… D. area with cold seasonal temperatures

To determine when a volcano erupted, Michael used a sample of a mineral that formed when the lava cooled and became solid rock. He measured the amount of argon-40 in the sample to find how much potassium-40 had decayed since the rock formed. What else would Michael need to know to find the age of the mineral in years? A. the half-life of potassium-40 B. the amount of energy released C. the mass of a potassium-40 atom D. the time it takes argon-40 to decay

AND THE ANSWER IS…………… A. the half-life of potassium-40

GOOD LUCK!!!

Unit 7 Test Review