Glossary

Direct Search- Searching directly for life (for example, searching on Mars itself for life)
Hypothesis- educated guess
Indirect Search- Searching indirectly for life- using telescopes to analyse signals, looking for signals of intelligent extra-terrestrial civilizations
Macroevolution- many changes over a long period of time
Seasonal cycles- The seasons on a planet (eg: Spring, Summer, Fall, Winter
SETI- Institute that searches for signs of extra-terrestrial life (both indirectly and directly)
Subterranean- Under the surface