QUESTI0N: 
How will our rovers determine if there is life on Mars?

ANSWER from Jack Farmer on November 20, 1996: 
It will be quite difficult, I think, for a robotic mission to determine
conclusively whether life ever developed on Mars. We think we will be
looking for microscopic fossils and evidence of life's chemistry. This
will be most conclusively done in labs on Earth, and so we have been thinking
in terms of sample returns of Mars rocks that can be studied here. But we
have to find the right rocks and that is where rovers will be invaluable
tools in exploration!