News by Levels · Level 2 · For teachers
Teacher guide & answers
In this lesson: Connect several estimation methods with a limited fossil sample.
Teeth Reveal Clues About a Giant Rodent
How to use these two pages
Give learners the student worksheet. It contains the story and questions, without the answers. Keep this guide for yourself. Use it to lead the activity and explain the answers afterwards.
Student worksheetA simple 15–20-minute lesson
- Before reading · 2 minutes
Show the title. Ask: “What do you think this story is about?”
- Read and answer · 8–10 minutes
Give out the student worksheet. Learners read for the main idea, then reread to answer the 2 questions. They can compare answers with a partner.
- Discuss and write · 5–8 minutes
Check the answers below together. Ask learners to point to the clue in the story, then finish with the open question.
Adjust the support: Let learners use word help or Level 1 if needed. For a challenge, compare the wording in another level. This activity is not a proficiency test.
Answers to the 2 questions
The question numbers match the student worksheet. Each answer includes a reason and the clue learners can find in the story.
How did researchers estimate body mass?
Correct answer: A — Using seven methods
Why: The first paragraph explicitly says seven methods estimated its body mass.
Clue in the story: Fossil teeth from Thailand belong to Yakamys sirindhornae, a rodent from about 34 million years ago. Researchers used seven methods to estimate its body mass.
What is the comparison with other known rodents from that era?
Correct answer: C — About twice their size
Why: The second paragraph gives the approximately twofold comparison.
Clue in the story: Their estimate is around 30 kilograms, about twice the size of other known rodents from that era. Limited fossils leave uncertainty.
The open question: accept different answers
Ask learners: Explain the estimate and why it still needs qualification.
One possible answer: Seven methods produced an estimate of around 30 kilograms, about twice the size of other known rodents from that era. The fossils are limited, so the figure remains uncertain.
This is an example, not the only correct answer. Look for a relevant idea, a reason and the learner’s own words. Learners can answer aloud or write one or two sentences.
Grammar to discuss
Evidence limits certainty
Limited fossils leave uncertainty
Limited describes the small amount of fossil evidence; uncertainty remains even when several estimation methods are used.