- Scientists studied shark and ray fossils.
- They looked at fossils from a very long time.
- They wanted to know why species die.
- The team found that young species die more.
- Older species usually survive longer.
- Sometimes many species disappeared at once.
- Sometimes new species appeared after loss.
- Now humans add extra pressure on these animals.
Difficult words
- fossil — an old animal or plant in rockfossils
- species — a group of similar animals or plants
- die — to stop living and not exist anymore
- survive — to continue living after danger or time
- disappear — to stop being seen or go awaydisappeared
- pressure — a force or effect on people or animals
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Have you ever seen a fossil?
- Do humans add pressure on animals where you live?
- Would you visit a museum with fossils?
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