The Canals That Late 19th and Early 20th Observers Thought

Multiple Choice

The canals that late 19th and early 20th observers thought they saw on Mars turned out to be:

A) optical illusions
B) enormous cracks caused by extensive plate tectonics on Mars
C) very narrow oceans of water
D) huge chains of thousands of large volcanoes
E) built by the same race of ancient martian engineers who constructed the "face on Mars"