11.   The carbonates are a clue that the Martian rock had been exposed to water, a prerequisite for life.

12.   The researchers say the findings suggest that NASA should not be overly cautious about Martian rocks brought back to Earth by a future space probe.

13.   The results will be the first determination of the composition of Martian rocks.

14.   The same sort of back-and-forth happened when scientists examined martian rocks directly for signs of life.

15.   The rover, called Sojourner, can now resume its chemical analysis of Martian rocks.

16.   Until Sojourner detected quartz in its first Martian rock earlier this week, the mineral was not known to exist anywhere in the solar system except on the Earth.

17.   Without the Web, few would know that scientists can be whimsical, as when they named nearby Martian rocks Barnacle Bill and Yogi.

18.   Organic chemicals found in a Martian rock may be contamination from Earth and not evidence of life on the Red Planet, new studies suggest.

19.   Scientists had brainstormed fixes for the potentially crippling problem that left the rover stuck aboard the lander with tantalizing martian rocks just out of reach.

20.   Until now, most scientists concluded that the riddled Martian rocks were volcanic matter, textured by gases escaping the cooling lava.