Fossils and Evidence of Past Life — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. In Grade 3 science, a coiled shell fossil in gray limestone most likely comes from which animal group?
A) Ancient ocean ammonites
B) Desert spiders
C) Flying dinosaurs
D) Giant ferns
Ammonites had coiled shells and lived in ancient seas, and limestone often forms there.
2. In Grade 3 science, a fossil leaf with long veins found in coal probably lived in what place?
A) An icy tundra
B) A warm, wet swamp
C) A sandy desert
D) A deep ocean
Coal forms in warm, wet swamps, so fossil leaves in coal belonged to swamp plants.
3. In Grade 3 science, a sharp triangle tooth fossil the size of a hand most likely came from which modern relative?
A) A butterfly
B) A robin
C) A shark
D) A snail
Sharks have sharp triangular teeth that change little over time, matching many fossil teeth.
4. In Grade 3 science, a trilobite fossil tells a paleontologist the rock formed in which environment?
A) High mountain peak
B) Dry desert dune
C) Ancient shallow sea
D) Hot volcanic lava
Trilobites lived on ancient shallow sea floors, so their fossils mark old ocean rocks.
Part B: Fill in the Blank
Write the correct answer on each line.
1. In Grade 3 science, a fossil's shape tells scientists what the animal ate and how it lived.
A fossil's shape gives clues about diet, movement, and habitat for the ancient animal.
2. In Grade 3 science, finding many different fossils in one layer shows that area had a rich ecosystem.
Many fossils together mean many species lived there, showing a rich past ecosystem.
3. In Grade 3 science, the oldest fossils are usually found in the deepest rock layers.
Sediment stacks with newest on top and oldest beneath, so deep layers hold the oldest fossils.
4. In Grade 3 science, a living species whose ancestors appear as fossils is called a modern relative.
A modern relative shares ancestors with a fossil species, like sharks with ancient sharks.
5. In Grade 3 science, a fossil that is no longer found alive anywhere on Earth is extinct.
Extinct species, like trilobites and mammoths, only live on through their fossils.