Which of the following suggests Mars may have once supported life? Fossils have been found on Mars' surface.
Flood plains indicate water may have existed in the past.
Rocks on the planet's surface have high concentrations of iron.
Mars' atmosphere contains carbon dioxide, just like Earth's atmosphere.

Which of these is not an example of molecular homology? 1. use of dna and rna as genetic material 2.use of glycolysis as the first step in cellular respiration in both plants and animals 3. the lack of an igf-1 gene in prokaryotes 4. the use of aldolase b to break down fructose in bacteria, plants and animals