Added on Dec. 10, 2016: Macromolecule Means Life, Past or Present.
Macromolecules (see https://en.wikipedia.org/wiki/Macromolecule ) are very large molecules. Macromolecules usually contain thousands of atoms. They are over 1,000 Daltons in weight while “complex organic molecules” are less than 215 Daltons in weight.
Only life can produce macromolecules. Non-biological mechanisms cannot produce organic macromolecules (see notes below). So, macromolecules found on Mars means past or present life found on Mars. Even if the macromolecules came to Mars in a meteorite, the macromolecules still originated from life, past or present.
Note 2: There is no pathway for macromolecules to be formed in the absence of life (via abiogenesis or prebiotic complex organic molecules). Added on Dec. 14, 2016: Both Life and Meteorites Contributed to Organics All Over Mars. “New analysis from NASA's Mars Curiosity rover shows that the red planet is likey flush with organics.” ”I am convinced that organics are all over Mars,” said Jennifer Eigenbrode, a biogeochemist and geologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.” ”They're all over the surface and they're probably through the rock record. What that means is something we'll have to talk about,” Eigenbrode said last week during a National Academy of Sciences workshop about the search for life beyond Earth.”