Earth systems crossword puzzle - easy

123456789
Across
  1. 3. the layer of earth on which we live on
  2. 4. The name of the "supercontinent"
  3. 5. They layer between the crust and the mantle and is also where the tectonic plates are
  4. 8. The man who came up with the theory of continental drift
Down
  1. 1. this is the substance that makes up most of the outer core
  2. 2. The thickest layer of earth and also where convection currents occur
  3. 3. the inner layer of earth and is made of iron and nickel
  4. 6. the technology used by Harry Hess to come up with the theory of seafloor spreading
  5. 7. The geologist that used sonar to make the theory of seafloor spreading
  6. 9. the study that both Alfred Wegener and Harry Hess used