Hi Sherry,
Thanks for the question. The key to solving any LR question always lies in the stimulus. So, let's start there first, and then take a look at the answers you mention.
In the stimulus, the author concludes that "the people who spoke Proto Indo European, the language from which all Indo European languages descended, lived in a cold climate, isolated from ocean or sea." Why does the author draw this conclusion? Because they didn't have a word for sea, but did have words for winter, snow, and wolf. This is a causal argument then, and the author is saying that the cause of this particular word usage is the location where the people who spoke Proto Indo European lived.
Ok, with a clear understanding of what the is occurring in the stimulus, our chances for avoiding wrong answers and finding the right answer increase
Let's look at each of the answers you mention:
- Answer choice (A): This answer looks attractive at first. But, it's difficult to say this undermines the author's broad claim about the location of these peoples. Maybe they traded with another culture, and fish was an item they received. In any event, it seems tough to accept that this single, small example refutes the conclusion.
Answer choice (B): As you note, this is the correct answer choice. If this answer is true, the lack of the word "sea" is not notable at all, and this answer suggests that the lack of that word is not an immediate reason to suspect they lived where the author claims they lived.
Answer choice (D): This answer is very similar to (A), and any time you see two answer that are this similar, they are typically both wrong. "Heat" as a concept could come from the fires they made, for example, and there's nothing suggesting "heat" here has to be tied to general climate indicators (which, if that was the case, would make this answer more attractive).
As far as Weaken questions in general, let me give you two pieces of advice that may help:
- 1. Isolate the conclusion, and attempt to weaken the connection for it.
The most important thing in any Weaken question is for you to identify the exact nature of the conclusion. Otherwise, you will be attracted to answers that seem to weaken the conclusion, but don't weaken the exact conclusion in the argument. And, considering that the typical LSAT answer choice won't directly contradict the premises or conclusion, look to then break the leap that the author makes in going from the premises to the conclusion.
2. Personalize the argument.
When approaching LSAT questions, often the tendency is to attempt to be as clinical and as coldly rational as one can be. While I'm all for rationality and a cold-hearted execution of each question, one of the ways to succeed on Weaken questions is to imagine that you are personally involved in the argument. For example, imagine that you are the one announcing the argument to a crowd of reporters, and that each answer choice is a challenging comment from a reporter. How would you respond? Would you be forced to surrender and grant the point (that's the correct answer, then), or would you have a retort that would put that reporter in his or her place (meaning that answer is wrong)? Seeing the argument and answer choices from a connected perspective often makes wrong answer much more obvious, and correct answer easier to identify.
There is more to be said than the above two points, of course, but what I've often found is that when someone has general difficulty with Weaken questions, they get a big, immediate boost by consistently thinking about and applying the two points above.
Please let me know if that helps. Thanks!