Soru

### Martian Methane Debate

Methane ($CH_4$) in the Martian atmosphere is unstable because it is rapidly destroyed by solar ultraviolet radiation. Therefore, its continued detection suggests an active underground source. Two scientists present different hypotheses regarding the source of this methane.

Scientist 1
Martian methane is produced abiotically (without life) through a geological process called serpentinization. In this process, liquid water circulating deep within the Martian crust reacts with olivine (a volcanic mineral) and dissolved carbon dioxide ($CO_2$). This chemical reaction produces magnetite, serpentine, and $CH_4$ gas at temperatures between $100^\circ\text{C}$ and $250^\circ\text{C}$. The methane then travels through crustal fractures to enter the atmosphere. No organic processes or living organisms are required to produce the observed methane.

Scientist 2
Martian methane is produced biotically (by living organisms) by methanogenic microbes located in subsurface aquifers. These microbes consume hydrogen ($H_2$) and carbon dioxide ($CO_2$) to generate energy, producing $CH_4$ and water ($H_2O$) as metabolic byproducts. Because the surface of Mars is dry and exposed to lethal radiation, these microbes must inhabit warm, deep aquifers where geothermal heat keeps water in liquid form. The high efficiency of biological methane production best explains the observed seasonal fluctuations in atmospheric methane levels.

Based on the descriptions provided, both Scientist 1 and Scientist 2 would agree that which of the following pairs of substances must be present beneath the surface of Mars for methane to be generated?