Mars appears red because its surface rocks contain iron oxide, also known as rust, which gives the planet its reddish appearance. This rusting occurs due to the oxidation of iron minerals in the Martian soil when they come into contact with the small amounts of water vapor and oxygen present in Mars' atmosphere.

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Why Is Mars Red

Question 22

Multiple Choice

Why is Mars red?

A) Its surface is made of ices that absorb red light.
B) Its surface is made of ices that absorb blue light.
C) Its atmosphere scatters blue light more effectively than red light.
D) It is made primarily of red clay.
E) Its surface rocks were rusted by oxygen.

Correct Answer: