Complex sentence: However, the GCMS measured no significant amount of organic molecules in the Martian soil, in fact the strongest organic concentrations it measured were minute trace contaminants brought from Earth, left over from the assembly and cleaning of the sample chambers and instruments.
Split into simpler sentences: However, the GCMS measured no significant amount of organic molecules in the Martian soil. The strongest organic concentrations it measured were minute trace contaminants brought from Earth, left over from the assembly and cleaning of the sample chambers and instruments.