Why must lander probes on Mars be sterilized before launch?
A) to prevent terrestrial microbes hitching a ride on the probe and contaminating the Martian surface
B) to prevent terrestrial microbes destroying the electronics in the probe during its passage to Mars
C) to prevent Martian dust from building up on the probe on the surface
D) to prevent Martian microbes from contaminating the lander probe
Question 2
Telescopic observations of distant galaxies have shown that the universe is
A) expanding
B) contracting
C) static and unchanging
D) infinite in size
Mars Methane map
Phobos in color by Mars Reconnaissance Orbiter - HiRISE
Viking Mars Lander
Ways to prevent heat waves
Mars using Google
Valves in veins prevent the backflow of blood