In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

[Q]: Article: Most of us remember our teachers well. Three successful Americans talk about the teachers who encouraged them. Kevin Henkes is an excellent author and illustrator whose books include Lilly's Purple Plastic Purse, The Year of Billy Miller, and Kitten's First Full Moon, which won the Caldecott medal. "I grew up in the school days of silent hallways and desks in neat,evenrows. One day, our forth-grade teacher allowed the class to move the desks out of rows intogroups of four. It might seem like a small thing now, but it taught me that you could do things differently; you could think outside the box. That teacher helped me view my world differently. Good teachers can change lives." Katherine Applegate has won many awards for her books, including the Newbery Medal for The One and Only Ivan. She also created the Animorphs series with her husband, Michael Grant."My sixth-grade teacher in Michigan sensed that 1 wanted to write,so one day she sent me home to write about the word'blue'in as many ways as possible. Because of that,for the first time in my life, I thought of myself as someone with special skills as a writer, someone who was unique. My teacher's actions said'I see something special in you.'" In his role as U.S.Secretary of Education, Arne Duncan is in charge of the department that collects data and directs research on America's schools."My high school English teacher was amazing. She challenged us to express our ideas clearly in class and in our writing. There was no such thing as a bad question. She wanted to hear from us and encouraged us to speak up and express ourselves. She pulled things out of me that I didn't know I had inside. I think that is the genius of good teachers."
Answer: by asking her to write in various ways.
[A]: How did the teacher encourage Katherine Applegate?

[Q]: Article: Science Daily (Apr. 27, 2008)-- Dutch ecologist Roxina Soler and her colleagues have discovered that subterranean and aboveground herbivorous insects can communicate with each other by using plants as telephones. Subterranean insects issue chemical warning signals through the leaves of the plant. This way, aboveground insects are warned that the plant is already "occupied". Aboveground, leaf-eating insects prefer plants that have not yet been occupied by subterranean root-eating insects. Subterranean insects send out chemical signals through the leaves of the plant, which warn the aboveground insects about their presence. This messaging makes it possible for spatially-separated insects to avoid each other, so that they do not compete for, the same plant. In recent years it has been discovered that different types of aboveground insects develop slowly if they feed on plants that also have subterranean insects and 'vice versa . It seems that a mechanism has developed through natural selection, which helps the subterranean and aboveground insects to communicate with each other. This avoids unnecessary competition. Through the "green telephone lines", subterranean insects can also communicate with _ , namely the natural enemy of caterpillars . Parasitic wasps lay their eggs inside aboveground insects. The wasps also benefit from the signals sent by the leaves, as these help them find more insects for their eggs. The communication between subterranean and above- ground insects has only been studied in a few systems. It is still not clear how widespread this phenomenon is, say the researchers.
Answer: By sending signals through the leaves.
[A]: How do subterranean and aboveground insects communicate with each other?

[Q]: Article: Three "Great Walls" built around the United States' Tornado Alley could reduce tornadoes from destroying billions of dollars in property and endangering millions of lives, a physicist has claimed. Professor Rongjia Tao of Temple University, Philadelphia unveiled a proposal this week calling for the construction of three 1,000-foot barriers up to 100 miles long, which would act like hill ranges and soften winds before tornadoes could form, the BBC reports. The $16.9 billion plan would call for the faux hill ranges in North Dakota, along the border between Kansas and Oklahoma, and in Texas and Louisiana, ostensibly saving billions of dollars in damage every year, Tao said. The walls would not shelter towns, he said, but instead would soften the streams of hot southern and cold northern air that form tornadoes when they clash in the first place. But critics laughed at Tao's proposals. Leading tornado experts pointed to areas that are already protected by hill ranges the size of the barriers Tao is proposing, yet still have plenty of tornados, like parts of Oklahoma, Arkansas and Missouri. And even if the plan did work, it would create more problems than it would solve, scientists said, by creating catastrophic weather side effects. "Everybody I know is of 100% agreement - this is a poorly conceived idea," Professor Joshua Wurman of the Center for Severe Weather Research. "From what I can gather his concept of how tornadoes form is fundamentally flawed . Meteorologists cringe when they hear about 'clashing hot and cold air'. It's a lot more complicated than that."
Answer: The different opinions on the proposal that the walls will reduce the loss caused by tornadoes.
[A]:
What's the main idea of the passage?