Archaeologist: Neanderthals, a human-like species living 60, 000 years ago, probably preserved meat by smoking it. Burnt lichen and grass have been found in many Neanderthal fireplaces. A fire of lichen and grass produces a lot of smoke but does not produce nearly as much heat or light as a wood fire. Which one of the following, if true, would most weaken the archaeologist's argument? ['In close proximity to the fireplaces with lichen and grass are other fireplaces that, evidence suggests, burned material that produced more heat than smoke.', 'Some of the fireplaces containing burnt lichen are in regions in which lichen is not believed to have been plentiful and so would have had to have been brought in from some distance.', 'In the region containing the Neanderthal fireplaces in which lichen and grass were burnt, no plants that could be burned more effectively to produce heat or light were available 60, 000 years ago.', 'There is clear evidence that at least some groups of Neanderthals living more recently than 60, 000 years ago developed methods of preserving meat other than smoking it.']