The Viking Landers Pyrolytic-Release Experiment,which Was Used to Look for Life

The Viking Landers pyrolytic-release experiment,which was used to look for life on Mars,was based on the idea that in

A) respiration,organisms take in some gases and release others,thus altering the composition of the atmosphere around them.
B) photosynthesis,gases are removed from the atmosphere and incorporated into the organism.
C) running around a maze,an organism's heart rate goes up.
D) metabolism,organisms consume nutrients from the soil and produce gases as a by-product.