Results from the Phoenix lander and Curiosity rover suggest that the positive result from the Viking Labeled Release experiment was probably due to
A) the destruction of organic molecules by oxygen released when perchlorates in the soil decomposed on heating
B) terrestrial contamination from the robotic arm which took the samples
C) a malfunction in the experiment
D) high levels of radioactivity in the soil

Question

Quizplus · Accepted Answer

Both the Phoenix lander and Curiosity rover found evidence of perchlorates in the Martian soil, which can release oxygen when heated and potentially destroy organic molecules. This is the most likely explanation for the positive result from the Viking Labeled Release experiment. B and D are unlikely as extensive measures are taken to prevent terrestrial contamination and there is not significant radioactivity on Mars. C is possible but less likely given the consistency of the results from multiple missions.

Results from the Phoenix Lander and Curiosity Rover Suggest That