Planetary Research in Recent Years Has Shown That

Planetary research in recent years has shown that

A) Mars's northern hemisphere was under an ocean for a billion years.
B) like Earth, Mars has gone through multiple mass extinctions.
C) by being beyond the asteroid belt, Mars was never pelted with meteorites.
D) Martian canals really were constructed by alien engineers.
E) strange tectonic pressures on Mars are projecting meteors toward Earth.