How will the right answer fit in terms of support and conclusion?

Only the right answer will support disagreeing with the conclusion.

Highlight the main conclusion in the passage, if there is one:

it is unlikely that nanobes truly are living things. They are probably inanimate artifacts of the clay’s microscopic structure

[BACKGROUND]. However, [CONCLUSION]. [MORE CONCLUSION], because [SUPPORT].

Map the wording of the answers to the wording of the passage:

(A) No known form of bacteria is complicated enough…

The argument isn’t about bacteria. The author just compares “nanobes” to bacteria in the background, but they never get mentioned in the conclusion or support. So info about bacteria isn’t going to support or weaken the argument at all.

(B) …can combine to form a multicelled structure and then reproduce…

I see people eliminate this answer all the time, since “single-celled” and “multicelled” don’t come up in the passage. And honestly, I can’t fault you if that’s what you did. But the LSAT will. A lot of top scorers come back to this one after eliminating everything on the list.

But this answer does effectively push back against the passage, which says a nanobe probably isn’t alive because it’s “too small to contain a reproductive mechanism”. This is calling out another possible way to reproduce even if a single nanobe is too small. On this list of choices, that’s enough to be the one that “most seriously weakens” the argument.

(C) …some scientists claim are bacteria…

Be careful, this isn’t actually adding any new info. The passage already told us the nanobes are way smaller than “the smallest known bacteria”. Since this is just what “some scientists claim”, it doesn’t change the facts at all. And thus, it doesn’t weaken the argument.

(D) Previous definitions of life…

That’s bringing in something new without directly mapping to the support or conclusion. Was the “geologist” in the argument using the “previous” definition? Did they use one of the “inferior microscopes”? Would an inferior microscope cause them to get the nanobe’s size wrong? We don’t know any of the answers. If you’re picking this, you’re assuming what the answers are on your own. That’s no good. At least the reasoning in (B) is directly related to the reasoning in the passage.

(E) Animals such as cold-blooded lizards…

…are never mentioned either. Since the argument is about whether something is alive at all, a comparison between different kinds of animals doesn’t help. We know all of them are “living things” even if some are “simpler” or “larger” than others.

(B) is the correct answer.