LR Question 21 Explanation
QUESTION TEXT: In several countries, to slow global warming, many…
QUESTION TYPE: Necessary Assumption
CONCLUSION: Government incentives to plant trees increase global warming.
REASONING: Trees don’t store CO2 as well as native grasses do. Governments give farmers incentives to plant trees.
ANALYSIS: You can conclude that the incentives aren’t encouraging the best possible policies. Farmers could trap more CO2 if they planted grasses instead of trees.
Further, if farmers remove native grasses to plant trees, then the incentives are clearly bad.
But you don’t know what farmers would do without the incentives. Maybe farmers would plant crops, rather than grasses. Crops might not store CO2. There’d still be no native grasses. So the argument assumes farmers would plant grasses if there were no incentives.
___________
- It doesn’t matter. The stimulus said that trees reduce CO2 on average. The point is that grasses are even better at reducing CO2, so we’re not encouraging the best use of the land.
- The only necessary assumption with respect to trees is that at least some farmers plant trees in response to incentives. “Most” statements are poor answers on necessary assumption questions, as the negation of most is just ‘not most’, which could be as high as 50%.
- This might strengthen the argument, but it’s not necessary. It just adds an additional reason trees are bad. We don’t need two reasons.
- CORRECT. Negate this answer. If no trees are replacing native grasses, then there’s no problem.
Negation: No trees planted due to the incentives are planted where native grasses grow. - This isn’t necessary. In fact, the argument is stronger if this isn’t true and many governments promote native grasses.
I got tripped up over the stimulus phrasing: “helping to hasten global warming,” which is why I fell for A. If the trees are not as effective as native grasses, but they’re still storing carbon dioxide (albeit not as well as native grasses), is this “hastening” global warming? Halp!
It’s important to be precise here, which is where you might be getting tripped up. The conclusion isn’t that trees in general are hastening global warming, it’s that the government policy is.
For that to be true, we need to assume that these incentives to plant/grow trees are displacing something that would have been more effective at reducing CO2. That’s why D is necessary. If some of the trees are being planted where native grasses would have grown otherwise, then the net effect of the government incentive is a worse CO2 absorption rate, which supports the idea that the policy is hastening global warming.
So, basically. If the government didn’t give these incentives, we would naturally have a bunch of native grass growing in some of these areas, which is even MORE effective than trees at absorbing and storing CO2. But since these farmers are now planting trees in these areas instead, they’re actually choosing a use of land that is less effective at slowing global warming, thereby hastening it. Hope that helps!
D is sufficient, not necessary.
I could have D not be true and still have a completely valid argument. For example, say the trees that are being insentivised put a certain chemical into the soil that disallows the grass from being grown (or anything to that effect). Boom. We have a perfectly good argument and I did not use D one bit. D may be sufficient, but it’s definitely not necessary.
Someone please explain to me what I am missing. Thanks.
D isn’t sufficient. If 0.000001% of trees are planted and replace native grasses, that leaves all the rest to be planted in areas where they don’t replace native grasses. So in that case it is likely the trees help reduce CO2.
I’m not sure I understand your reasoning for how D is not necessary. But, to restate it: the entire argument is that trees cause harm by replacing grasses. This is only possible if trees are planted where grasses grow. If they aren’t, it’s hard to see how trees interfere with grasses. Maybe if tree seeds drift and replace the grasses over time but that’s pretty tenuous.
Note: This is an old comment but I wanted to clarify the point.
Preptest 65 section 1 question 21
I don’t understand why “E” is incorrect. The argument had to do with incentives. If the government were interested in promoting the growth of grasses (the negation) then we would have the argument be weaker. Because they are not interested in the promotion of grasses the farmers can plant whatever they want. Which in this case is trees? Had they promoted grasses the farmers would have planted more grasses. Which is what E essentially says
Consider what happens in the negation of E:
1. Governments ARE interested in planting grasses
2. But they’ve been promoting trees. Trees are worse than grasses.
3. So the tree policies are directly undermining the grass policies.
This series of facts STRENGTHENS the argument. So negating E strengthens the argument, which is the opposite of what we want to do.
If governments aren’t promoting grasses, then the tree policies may be beneficial. The policies aren’t the best possible policies, but they may be better than nothing.