Crossword Puzzle

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Across
  1. 2. Which ancient civilization built the pyramids of Giza?
  2. 4. Which country is home to the Great Barrier Reef?
  3. 5. In which layer of Earth's atmosphere does weather occur?
  4. 7. What is the largest internal organ in the human body?
  5. 8. In math, what is the term for a number that has no fractions or decimals?
  6. 9. What is the main gas found in Earth's atmosphere?
Down
  1. 1. Which type of rock is formed from cooled lava or magma?
  2. 3. What is the process by which a caterpillar transforms into a butterfly called?
  3. 4. What is the chemical symbol for gold?
  4. 6. Who wrote the play "Romeo and Juliet"?