PASSAGE 1
The sun,the planets and their moons form the part of the solar system. But there are a number of smaller, minor bodies which also belong to it and travel,like the
planets, in orbit around the sun. These are the asteriods, meteors and comets. The sun and all these bodies travel through space as a unit or 'family' held together
by the sun's gravitational attraction.

The warmth and light of the sun are the most important things to us on earth, for without them there would be no life of any kind. The sky would always be inky black and the
emperature would be deadly cold. The fiery sun is a great globe of hot, glowing gases. We can call it our star, for that is what it is - just another star. As far as stars go, it is very ordinary, being neither particularly big nor particularly brighter but there are also many that are much smaller and dimmer.

What are the prospects of life elsewhere in the solar system, besides earth? Are there any Mercurions, Venusians, or Martians? From our present knowledge of the
conditions on other planets, can we say that it is most unlikely that there is any other life as we know it.

Life as we know it definetely could not exist on Mercury because it is too hot. And Jupiter and the outer planets are much too cold. The only planet where life as we know
it had been considered possible are Venus and Mars. But the available evidence from the latest Russian and American space probs makes the possibility remote.

What about life outside the solar system? The sun is but one of millions of millions of stars in the heavens. It would be incredible if there were no other stars with planetary
systems like ours. It is likely that there are within the universe planets on which conditions are much like those on earth. Why then should there not be other life elsewhere
similar to our own? Why not indeed? This ia a mystery which we might one day solve, when we learn more about how life began and when, if ever, we can travel to the stars.
Adapted from: The Children's Encyclopedia, ed Kenneth Bacley, Londonb
According to the passage, planetary bodies are held together by the

• A.mercurions
• B.meteors and comets
• C.moon's gravitational attraction
• D.sun's gravitational attraction
• E.venusions.