- Thu Nov 17, 2016 7:05 pm
#30657
If you are a Neanderthal using lichens and grass in your fireplace, you might be doing it to produce light, heat, or smoke. Because lichens and grass are inferior to wood as a means of producing heat, if you are cold or want light and have the option of using wood, you will use wood. Answer choice (A) suggests a scenario where some fires were made of wood and some were made of lichens and grass. In that scenario, it seems that wood was available. So, the inference is that the lichen and grass fires were used for something else. This strengthens the argument (although of course there are still other ways the conclusion still may be untrue; for example, maybe wood was scarce and there was not enough for everyone).
Answer choice (B), on the other hand, describes a scenario where there was nothing between than lichens and grass to produce heat or light. If that were the case, it would be reasonable to assume the fires were used for heating and light, without jumping to the conclusion that they were used to smoke meat.
Here's an analogy--feel free to ignore if you understood the above:
An alien sees a couch and concludes it is used for sitting down with family and friends. Then it walks into your apartment and sees a bed and a couch-- and is strengthened in its belief that the couch was not for sleeping because you have a bed that seems much more comfortable for sleeping. This is like answer A. In another scenario, a stranger walks into your apartment and sees that you have a couch and nothing else that is soft that you could lie down on. That weakens the conclusion that the couch is used for sitting down with family and friends because perhaps it is used only for sleeping. This is like answer choice B.