Generally, a higher biodiversity level indicates a healthy ecosystem that is capable of supporting life well. (scientificamerican.com)
If certain chemicals, like oxygen and methane, are detected it would be a strong indicator that a planet is capable of supporting life. (news.vanderbilt.edu)
Baross says he thinks Europa is the second most likely place in the solar system, after Mars, to be capable of supporting life as we know it. (newscientist.com)