9. Life on Mars

9.1. Mars and Astrobiology

9.2. Mars as a Planet

9.2.1. Requirements for Life to Originate on a Planet

9.3. The Potential for Life on Mars

9.3.1. Liquid Water

9.3.2. Climate Change

9.3.3. Biogenic Elements and Energy

9.3.4. Potential for Interplanetary Exchange

9.4. The Viking Mission

9.5. Claims for Life in the ALH84001 Meteorite

9.6. Searching For Life on Mars