1.   And if Zare and NASA scientists are right, then the rock may house microscopic fossils of prehistoric martian microbes that squirmed within the martian crust long ago.

2.   Even if they turn out to be Martian microbes, they are long dead.

3.   From the rocky samples, scientists hope to extract Martian microbes, either fossil or extant, proving the reality of aliens.

4.   Goldin and the scientists cautioned that it was too early to be absolutely, positively sure that Martian microbes had existed long ago.

5.   Martian microbes may have trouble surviving on Earth.

6.   On returning from Scotland, I covered the spacecraft landings on Mars, where Martian microbes proved as elusive as Nessie.

7.   Now, the National Research Council wants them to worry a little more about the risk of invading Martian microbes.

8.   Other experts are dubious of Martian microbes and have long dismissed the gases as the byproduct of lifeless chemical reactions.

9.   Some have proposed that all samples be heat sterilized, to protect against unlikely Martian microbes.

10.   The rock contains hot-dog-shaped objects that may be fossilized Martian microbes.