RC Passage 4 Explanation
This is an explanation for passage 4 of LSAT preptest 65, the December 2011 LSAT. This passage is about restoring farmland to its natural state, and how pathogens make this difficult.
This section has paragraph summaries and an analysis of the passage, links to the explanations for the questions are below.
Paragraph Summaries
- It is difficult to restore farmland to its natural state. Nutrients are depleted and weeds have spread. A dutch experiment may speed things up.
- The experiment produced varying results.
- Microorganisms can speed up recovery. Farmed land is depleted of microorganisms.
Analysis
This is a complex passage. It’s very hard to keep track of everything that’s going on, or draw an overall conclusion. Sometimes you’ll get a reading comprehension passage you just don’t understand. When you do, try to get the key points as best you can. Then when you review, aim for complete understanding. This will help you on future passages.
Here are the key points underlying this passage:
- Farmed soil is depleted, we want to restore it.
- Biodiversity is good and helps us restore land.
- Thistles are bad.
- More diversity above ground helps restore land.
- More diversity underground helps restore land.
If a question asks about specific details, you can refer back to the passage. It’s very difficult to keep everything straight on a first read; I didn’t try.
I noticed that the experiments were well controlled. Every experiment showed that diversity helped.
The first paragraph describes the main goal: restoring the biodiversity of old farmland.
The rest of the passage describes how to restore farmland faster. It’s a way to help achieve the goal. The passage never modifies or criticizes the goal.
Lines 30-33 are potentially confusing. You should know there were four different types of plots:
- Corn: Lots of thistles
- Nothing: Lots of thistles
- Fewer varieties: some thistles, but thistles are eliminated from certain mats of grass.
- Most varieties: all thistles gone
The final paragraph is even more confusing. I’ll try to break down what’s going on. Imagine some land that’s been out of production for 20 years. It’s been left to grow wild.
Then we’ve got new land, near the old farm. This new land was farmed until recently. Now let’s name three plots, A, B and C:
Plot A: A field from the old farm. Has been out of production 20 years.
Plot B: A field from the new farm. Recently out of production. Covered with soil from plot A.
Plot C: A field from the new farm. Recently out of production. Not given any new soil.
The passage says that plot A does best, plot B does second best, and plot C does worst. We can conclude that the soil from plot A helps plot B, but there’s still some factor missing.
Disease micro-organisms are the problem. Both plots B and C have horrible creatures living underground that harm plants. Soil from plot A helps defend against these diseases, but more time is needed to eliminate them.
One helpful analogy is the human body. You probably know that microorganisms help you to digest food. For example, certain bacteria help you digest the lactose in milk. Without them, milk will cause problems. Likewise, certain bacteria harm you.
You can eat a perfect diet, but if your stomach is full of bad bacteria, you will not do well.
Good food is like clover and native grasses. Bad food is like corn and farming. Disease micro-organisms are like the bad bacteria that give you stomachaches. The soil from plot A is like probiotics: they help you digest food, but you need to solve the bad bacteria problem before you can say your digestion is good.
One small note. It’s easy to be confused about the word ‘overproduction’. This refers to total agricultural production in Europe. Overproduction means it’s too high.
If people only want 100 million tons of food, and Europe produces 110 million tons, then there is overproduction. Overproduction has absolutely nothing to do with how intensely a given piece of land is cultivated.
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