Scientists tell us so much about the moon, it is quite easy to tell what it is like. It's certainly not a friendly place. As there is no air or water, there can be no life of any kind. Mile after mile there are only plains  of dust with mountains around them above, the sun and the stars shine in the sky. If you _ the mountains' shadows  it will mean moving from terrible cold into great heat. The moon is also a very silent world, for sound waves can only travel through air. But from the moon, you can see a friendly sight. Our earth is shining more brightly than the other stars. It looks like a very large ball, coloured blue and green and brown. The Moon is a silent world because  _  .
there is no life there there is no air there there is no green tree there there is no water there