[问答题]
The diagram shows a solar system v
c:m*onfebb: vwg mflrv /8/6(ery similar to ours, where five planet
0n;voi:nm z.r1 kuz/ps orbit a ce
m;1u0v kno:/ r. pzznintral star.
1.Define the term “Goldilocks zone”.
2.1.Label with the letter R the planet that is least likely to have extraterrestrial life present.
2.2Explain reasons for your answer to part (i).
3.1.Some of the planets in this solar system have water present on them. Suggest where this water might have come from.
3.2.Explain why the planets referred to in part (i) have retained water, whereas others in this solar system have not.
4.Suggest one other biological molecule, other than water, that may be a sign of life on a planet.
