What We Still Do Not Know: teacher key

Dinosaurs, grade 11 edition, written for 11th grade. Scientists favor an asteroid but still argue about volcanoes, timing and survival. They also ask where feathers and bird hips came from.

Read the book. Print this page for the key.

Questions and answers

1. What does the 2016 hypothesis say helped bird ancestors survive?
   • Larger teeth
   • Toothless beaks that let them eat seeds (answer)
   • Living in caves only
2. How wide is the range in the 2021 estimate of T. rex numbers?
   • 1 million to 2 million
   • 40 to 42
   • 140 million to 42 billion (answer)
3. The Marshall range runs from 140 million to 42 billion. What does that suggest?
   • The true number is very uncertain (answer)
   • The number is known exactly
   • The number is small
4. According to the pages, how many times did the bird-like hip evolve?
   • Once
   • Five times
   • Twice (answer)
5. What does hypothesis mean in 'a 2016 hypothesis holds'?
   • A proven law
   • An idea that can be tested (answer)
   • A kind of fossil

Words

• hypothesis: testable idea
• camouflage: hiding colours
• pubis: hip bone
• signalling: sending signals