Hawk:

That's a good point. In the years leading up to the Mars landing, life detection experiments had to be designed and then carried to Mars and executed. It didn't take long for the question of "What is life?" to rear its ugly head. The decision was you scoop up a sample of the soil, feed it some kind of organic soup and, if it metabolizes it in some way, we'll call it life. On that basis, no life was found.

Bev and Jerry