Solve me

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Across
  1. 2. H2O
  2. 5. science mountain?
  3. 6. alphabet math
  4. 7. 'element'-ary science
  5. 9. yellow transportation
Down
  1. 1. lunch spot
  2. 3. welcomes morning riders
  3. 4. brass conductor
  4. 8. learning order