What Are Multiple Choice Questions (mcqs)?

Rice That Fights Global Warming

More than half the global population relies on rice as a regular part of their diet. But rice paddies have a downside for the planet too: they produce as much as 17 percent of the world's total methane emissions. That is even more than coal mining emissions, which make 10 percent of total! So Christer Jansson, a plant biochemist at the Pacific Northwest National Laboratory, spent the past 10 years developing SUSIBA2, a genetically modified rice plant that emits almost no methane.
Multiple choice question:
1. What is the negative effect of rice?

1. 
   It is regular part of more than half of the world population’s diet.
   
2. 
   Rice paddies emit more methane than coal mining industry.
   
3. 
   Its plantations produce 17% of the world’s total methane emissions.
   
4. 
   Rice has genetically modified sort SUSIBA2, which is harmful for health.
   

In this question key words are “rice” and “negative effect”.
Now let's consider all the answers:
Answer A gives us true, but completely opposite information from what we're looking for. The first sentence tells us that
More than half the global population relies on rice as a regular part of their diet.
But it is a positive effect! And we're looking for the negative one. So this answer is false.
Answer B also gives us true information, but it is not what you’re asked about. Look at the third sentence, which contains information that answer B uses:
That is even more than coal mining emissions, which make 10 percent of total!
This sentence is used only to highlight the negative effect, not to state it.
Answer C is correct. The second sentence clearly states the negative effect:
But rice paddies have a downside for the planet too: they produce as much as 17 percent of the world's total methane emissions.
downside = negative effect
As you see, it's very important to search key words or their synonyms in the text.
Answer D is irrelevant: it was not written anywhere that SUSIBA2 is harmful. This answer uses some words from the text just to confuse you.
Don't be caught by irrelevant answers! If you see that answer contains information that contradicts the text or was not stated at all, it's an irrelevant answer.