Spelling worlds by Tyrah.

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Across
  1. 2. a tunnel under a road for use by pedestrians.
  2. 4. take the place of (a person or thing previously in authority or use); supplant.
  3. 5. observe and direct the work of (someone).
  4. 6. a heading given to a subsection of a piece of writing.
  5. 7. lower in rank or position.t
Down
  1. 1. a US cartoon, TV, and film character having great strength, the ability to fly, and other extraordinary powers.
  2. 3. descend below the surface of an area of water.
  3. 6. a warship with a streamlined hull designed to operate completely submerged in the sea for long periods, equipped with a periscope and typically armed with torpedoes or missiles.