The Curiosity rover is currently searching for signs of life on Mars.What kind of evidence would most likely indicate the presence of living organisms on Mars?
A) Fossilized prokaryotic cells
B) Different nucleic acids and amino acids than those found on Earth
C) Fatty acid molecules
D) Complex molecules containing genetic information
E) Simple organic molecules

Question

Quizplus · Accepted Answer

Complex molecules containing genetic information would be the strongest indication of the presence of living organisms because they would demonstrate the existence of processes involved in the replication and expression of genetic information, which are characteristic of life. Simple organic molecules (option E) could potentially indicate the presence of non-living chemical processes, but would not provide evidence of life. Fossilized cells (option A) would provide evidence of past life, but not necessarily present-day life. Different nucleic acids and amino acids (option B) might suggest a different form of life altogether, but it is not clear that such alternative biochemistry is possible or probable. Fatty acids (option C) could be produced by non-biological processes, making them an insufficient proxy for the presence of living organisms.

The Curiosity Rover Is Currently Searching for Signs of Life