2. Which event occurred first? a the Mars centennial b Schiaparelli reported seeing canals. c Scientists sew natural surface marking on Mars. d Schiaparelli discovered the two Martian moons.
2. Which event occurred first? a the Mars centennial b Schiaparelli reported seeing canals. c Scientists sew natural surface marking on Mars. d Schiaparelli discovered the two Martian moons. 3 Which event occurred last?