The rock that sprang to Martian "life" late last summer

did not shock me by offering up apparent fossils of an extinct

alien form of life. I had long believed that the universe teems

with life elsewhere, and that our failure to find it simply

results from a lack of exploration. What did amaze me about (Line5)

the potato-size rock that fell from Mars was that it had trav-

eled millions of miles across space to land here, blasted

from world to world by a planetary collision of the sort that

purportedly killed off our dinosaurs, and had lain waiting

for millennia upon an Antarctic ice field, until an observant (Line10)

young woman traveling in an expedition party picked it up,

because she figured that it had come from another world.

How could she know such a thing?

In lines 5-12, the author suggests that the expeditioners’ discovery of the meteorite was surprising primarily because it