September 16, 2025

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Across
  1. 1. early Earth’s atmosphere lacked free _____ until cyanobacteria began producing it?
  2. 4. the world’s oldest wooden structure, nearly half a million years old, was discovered in Zambia in 2023? It shows early humans used advanced building _____
  3. 5. elephants call each other by unique _____, much like humans?
  4. 7. the first antibiotic, penicillin, was discovered by in 1928?
  5. 8. Egypt’s greatest monuments were built as royal tombs known as _____?
  6. 11. ancient Roman concrete is stronger today than when it was poured? Its chemical reactions make it self-healing over _____
  7. 12. scientists engineered spider _____ to be red by altering genes?
  8. 14. sharks existed before trees and before the rings of Saturn _____?
  9. 16. scientists have found microbes living in the frozen, salty lakes beneath _____ ice?
  10. 17. the Dead Sea is so dense with _____ that people float effortlessly on its surface?
  11. 19. the fastest-growing plant on Earth is _____, which can grow up to 3 feet per day?
  12. 22. the world’s most active volcano, Kīlauea, is located in _____?
  13. 24. the hottest planet in our solar system is _____, not Mercury, because of its thick atmosphere?
  14. 25. undersea earthquakes can trigger giant waves called a _____?
  15. 26. researchers found octopuses throw shells and silt at each other? Possibly as a form of _____
  16. 28. snowflakes form hexagonal patterns due to ice _____?
  17. 29. coffee is the national drink of _____, the largest producer of beans in the world?
Down
  1. 2. the longest-living vertebrate is a shark found near _____, which can live up to 400 years
  2. 3. during worst famines in Egypt, texts describe even resorting to _____
  3. 6. the Mariana Trench is the deepest part of the world’s oceans, reaching nearly 36,000 feet (about 7 miles) _____?
  4. 9. the first computer programmer was Ada Lovelace in the 1800s? She wrote algorithms for Charles Babbage’s Analytical _____
  5. 10. one bolt of _____ can contain enough energy to toast 100,000 slices of bread?
  6. 13. the only mammals naturally capable of sustained flight are _____?
  7. 15. tardigrades, or ‘water bears,’ can survive in space? They can endure freezing, boiling, and even _____
  8. 18. new islands sometimes appear in the Pacific due to undersea volcanic eruptions of _____
  9. 20. the Amazon rainforest produces only about 6–9% of Earth’s oxygen? Most oxygen is actually generated by ocean _____
  10. 21. whales in the Pacific have changed their migration routes due to climate change? Researchers track these shifts using satellite _____
  11. 23. a newly discovered fossil in China revealed a _____ sitting atop its eggs?
  12. 27. Saturn’s moon Enceladus shoots geysers of water into space? NASA found these plumes contain organic molecules beneath the _____
  13. 29. certain flowers evolve ultraviolet colors only visible to _____?