Martian surface features include gullies and runoff channels, which suggest that on the surface of mars.
a. plants could grow
b. there is life
c. liquid water once existed
d. humans can live

Which principle do modern democracies share with ancient athens? a. all people deserve equal rights. b. there should be no taxation without representation. c. people should vote on all matters that concern them. d. people should have a voice in government.