Solve the crossword to find the next clue..

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