How a Fossil Forms: teacher key

Fossils, grade 4 edition, written for 4th grade. Fossils are what is left of plants and animals from long ago. Learn how a fossil forms, which rock layers are older and what a fish with a flat head shows.

Read the book. Print this page for the key.

Questions and answers

1. What turns buried bones and teeth to stone?
   • Layers of silt
   • Cold wind
   • Water full of minerals (answer)
2. Which fossils are among the most common at La Brea?
   • Saber-toothed cats (answer)
   • Tiktaalik
   • Pakicetus
3. About how old are Tiktaalik fossils?
   • 375 million years (answer)
   • 10,000 years
   • Tens of thousands of years
4. Fossil A is in the bottom layer of a stack of rock. Fossil B is in a layer at the top. Which fossil is older?
   • Fossil B
   • They are the same age
   • Fossil A (answer)
5. What does asphalt mean?
   • Fine mud
   • Sticky tar (answer)
   • Hard bone

Words

• silt: fine mud
• minerals: rock bits
• asphalt: sticky tar