| A | B |
|---|
| long, narrow ellipses | orbits of most comets |
| meteor | burning meteoroid in atmosphere |
| liquid water | condition required for life on Earth |
| wide range of conditions | Earth life forms exist in a _____ |
| Europa | has possibliity of life due to water |
| Pluto | fewest moons of the outer planets |
| comet | develops a tail near the sun |
| meteoroid | possibly formed of comet or asteroid pieces |
| dried stream bed-like patterns | evidence that Mars once had life conditions |
| Mars | planet with two moons |
