Earth's Changing Surface — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. The rule that older rock layers lie below newer ones is called the Law of Superposition.
Grade 4 NGSS 4-ESS1 introduces the Law of Superposition for ordering rock layers.
2. A preserved trace or remains of an ancient organism in rock is called a fossil.
Grade 4 students learn fossils are evidence of past life recorded in sedimentary rock.
3. If a fossil fish is found in a desert rock layer, that area was once likely a sea.
Grade 4 NGSS expects students to infer past environments from fossil evidence.
4. Rock layers made from squeezed sand, mud, and shells are called sedimentary rock.
Grade 4 students connect sediment to sedimentary rock formation in horizontal beds.
5. In an undisturbed cliff, the very bottom layer is the oldest layer.
Grade 4 Law of Superposition states the bottom layer is the oldest in an undisturbed sequence.
6. Tiny pieces of broken rock that get pressed into layers are called sediment.
Grade 4 students link weathering, sediment, and the formation of rock layers.
7. Fossils of tropical plants in cold Antarctica show climate has changed over time.
Grade 4 NGSS uses fossil evidence to show Earth's climate and surface have changed.
8. Layers that were tilted by movement of Earth's plates are no longer horizontal.
Grade 4 students recognize that plate tectonic forces tilt originally horizontal layers.
9. A scientist who studies fossils to learn about ancient life is a paleontologist.
Grade 4 students learn paleontologists use fossils to study past organisms.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Law of Superposition
→ Older layers lie below newer layers
Older layers lie below newer layers
Fossil
→ Trace or remains of an ancient organism
Trace or remains of an ancient organism
Sedimentary rock
→ Forms from squeezed layers of sediment
Forms from squeezed layers of sediment
Tilted layers
→ Sign that plate movement disturbed the rock
Sign that plate movement disturbed the rock
Grade 4 NGSS 4-ESS1 students connect rock-layer vocabulary to evidence about Earth's past.