what are these things?

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Across
  1. 1. – A hard natural material found on the ground or in the Earth.
  2. 2. – The material on the ground where many things grow.
  3. 5. – Facts or knowledge that help us understand something.
  4. 6. – The form of an object, such as a circle, square, or triangle.
  5. 7. – The green part of a tree or other plant.
Down
  1. 1. – A tool used to measure the length of something.
  2. 2. – Very small pieces of rock, often found on beaches or in deserts.
  3. 3. – A liquid that people, animals, and other living things need.
  4. 4. – The mixture of gases that we breathe.
  5. 6. – A small piece or amount of something that we study or test.