The prevalence of iron-sulfide cofactors in living organisms may be evidence that life arose ___.a. in outer spaceb. on tidal flatsc. near deep-sea ventsd. in the upper atmosphere

Key Concepts: Origin Of Life, Iron-Sulfide Cofactors, Prevalence, Evidence Explanation: Iron-sulfide cofactors are found in many enzymes involved in essential biological reactions. These cofactors are thought to have played a role in the origin of life by catalyzing reactions that were important for the synthesis of organic molecules on early Earth, either on tidal flats or near deep-sea vents. Because iron and sulfur are also abundant in outer space and some meteorites have been found to contain iron-sulfide minerals, it is possible that these cofactors originated in space and were delivered to Earth via meteorites. However, the prevalence of iron-sulfide cofactors in living organisms is not necessarily evidence that life originated in space. Step by Step Solution: Step 1. Understand the question and key terms. The question is asking about the prevalence of iron-sulfide cofactors in living organisms and what this may indicate about the origin of life. Iron-sulfide cofactors are molecules that contain both iron and sulfur and are involved in many essential biological reactions. Step 2. Consider the options. Option a, 'in outer space', is possible but not necessarily supported by the prevalence of iron-sulfide cofactors in living organisms. Option b, 'on tidal flats', is a theory for the origin of life that involves the interaction of geochemical processes with organic molecules in shallow, warm pools or lagoons. Option c, 'near deep-sea vents', is another theory for the origin of life that involves the interaction of geochemical processes with organic molecules near hydrothermal vents on the ocean floor. Option d, 'in the upper atmosphere', is not a widely accepted theory for the origin of life. Step 3. Evaluate the options. Option a is not strongly supported by the prevalence of iron-sulfide cofactors in living organisms. Options b and c are both possible explanations for the origin of life that involve the interaction of organic molecules with geochemical processes. Option d is not a widely accepted theory for the origin of life. Step 4. Choose the best answer. Options b and c are both possible explanations for the origin of life that involve the interaction of organic molecules with geochemical processes, and could both be supported by the prevalence of iron-sulfide cofactors in living organisms. However, option c, 'near deep-sea vents', is generally considered to be a more likely explanation for the origin of life, based on laboratory experiments and observations of modern hydrothermal vents. Step 5. Provide the answer. The correct answer is option c, 'near deep-sea vents'. Final Answer: c