The atmosphere on the Moon has become so thin and dry it is impossible for us to raise food except in pressurized greenhouses.
8 seconds sound clip from Radar Men from the Moon - Mass Execution (S1E10).
You can hear this line at 00:06:03.692 in the Blu-ray version of the movie.
Quote context
[...]
- I see you have adopted our language.
- Yes.
- All our people are required to speak English so we can operate more efficiently in your country.
- Do you mind telling me why your men are carrying out that campaign of destruction on Earth?
- They are merely softening up your defenses for our impending invasion.
- Why do you want to invade the earth?
- And none of us can move outside without helmets.
- So we are planning a mass migration to your world.
- You'll find that conquering the Earth isn't so simple.
- Ah, but it will be. Because of our atomic weapons.
[...]