PrepTest 109

Correct. Argument or Facts:
Facts

Question Type:
Must Be True

Stimulus Summary:
Soil plowed in spring → Pigweed seeds buried all winter churned up and reburied right under surface
Brief exposure to sunlight stimulates receptors, which leads to germination
not Buried all winter OR not Exposure to sunlight → not Germination

Answer Anticipation:
First, let's be sure to note that the question stem provides some information as to what we're trying to draw an inference about. Here, it's about a field that will be plowed in the spring and where there were pigweed seeds in the soil all winter.

With that seed of information (pun intended), we should head into the stimulus tracking what we learn about such a field.

The opening line tells us that such a field will have the pigweed seeds churned up to the surface, where they can be exposed to sunlight, and then reburied, where they'll start to germinate. So the field here, if it's plowed when there's sunlight, will end up with germinating pigweed seeds. If it's plowed when there isn't sunlight, the last statement says that there will not be germination. Let's find an answer reflecting either of these possibilities.

Answer Explanation:
If the field is plowed at night, then there won't be sunlight, and so germination won't occur. If the field is plowed during the day, then there will at least occasionally be sunlight, leading to germination. As such, the field will have more pigweed if it's plowed during the day than at night, and this answer is supported by the stimulus.

Key Takeaway:
When the question stem provides you a starting point, take it. While we would have ended up in the same place even without the prompting from the stem, having that information as a starting point allowed us to know immediately what was and wasn't relevant in the stimulus, so we were flying with more information.

Incorrect. The stimulus notes that a lack of sunlight means there won't be any germination, whether that's because the field isn't plowed or it's plowed only at night. As such, neither field should really have any pigweed, so this answer is unsupported.

Incorrect. In both cases, there won't be sunlight, so there shouldn't be germination in either case and thus no pigweed.

Incorrect. The stimulus states that the brief exposure to sunlight results in germination, but it doesn't establish that longer exposure wouldn't lead to germination. And the final sentence establishes exposure to sunlight as a necessary condition for germination—not exposure to only brief periods of sunlight. As such, we can't infer that pigweed will grow only if it's reburied after it's exposed to sunlight.

Incorrect. The stimulus says that the seeds don't germinate "[w]ithout the prolonged darkness" that comes from being buried, so this answer is contradicted.