The paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Choose the missing words of the phrase or sentence.

If spaceships were launched from space or from the moon, the absence of weight would permit the ships to be launched with great speed at reduced pressures. A relatively small explosion would be enough to send a ship off at a very fast rate. And, since there is no atmosphere in space as there is on earth, the spaceship would meet with no resistance.

（） from absence of weight in space.