Sentence:  <WSD>Martian</WSD> meteorites (Fig. 1.3) are pieces of Mars that have been blasted off the surface, hurtled through space, and delivered to Earth [...]. We know they are from Mars because the noble gases, carbon, and nitrogen measured in shock melt pockets in certain meteorites have the same relative elemental abundances and similar isotopic ratios as the <WSD>Martian</WSD> atmosphere—a unique fingerprint [...]. 
Meaning of the word marked with <WSD> tags:  Of or relating to the planet Mars, or  its imagined inhabitants. (from 19th c.)