Solve the crossword puzzle to complete the checkpoint.

123456
Across
  1. 2. A large area filled with many trees and plants (6 letters).
  2. 5. The vast, deep body of saltwater covering most of the Earth's surface (5 letters).
  3. 6. A large body of water surrounded by land (4 letters).
Down
  1. 1. Earth's bright satellite that shines at night (4 letters).
  2. 3. The giant ball of fire in the sky that gives us warmth and light (3 letters).
  3. 4. A solid, hard material found on the ground, often made of minerals (4 letters).