Word Ladder 4

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Across
  1. 2. They fall from the sky.
  2. 4. This gas is one of the properties of the Sun.
  3. 5. It is a force that has kept all the celestial bodies in their position.
Down
  1. 1. The constellation that looks like a hunter.
  2. 2. It is the smallest planet in the Solar System.
  3. 3. It is the shape of the orbit.