Passage Summary: Pictures of a moon of Jupiter show ice that looks like it was moved by water, suggesting there is a warm sea underneath which could mean life has started there.

Conclusion: There is a possibility that life exists on Europa.

Reasoning: Photographic evidence of buckled ice suggests a warm sea exists beneath the surface, and scientists believe such seas are essential for the development of life.

Analysis: The claim about the warm sea functions as an intermediate conclusion. It is a sub-point that is supported by the primary evidence (the photographs) and then used to support the final conclusion (the possibility of life). When identifying roles, it is helpful to see how the pieces of the argument stack on top of one another. The sea is the 'middle man' in this logical chain.