It is a claim for which no support is provided in the argument, and that is used to illustrate the conclusion of the argument as a whole. It is a claim for which some support is provided in the argument, and that itself is used to support two distinct conclusions, neither of which is intended to provide support for the other. It is a claim for which some support is provided in the argument, and that itself is not used to support any other claim in the argument. It is a claim for which some support is provided in the argument, and that itself is used to support another claim that in turn lends support to the conclusion of the argument as a whole.
Biologist: Scientists have discovered fossilized bacteria in rocks 3. 5 billion years old. The fossils indicate that these bacteria were quite complex and so must have already had a long evolutionary history when fossilized 3. 5 billion years ago. However, Earth is only 4. 6 billion years old, so the first life on Earth must have appeared soon after the planet' s formation, when conditions were extremely harsh. This suggests that life may be able to arise under many difficult conditions throughout the universe.
Which one of the following most accurately describes the role played in the biologist's argument by the claim that the fossilized bacteria discovered in rocks 3. 5 billion years old must have had a long evolutionary history?