In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Input: Consider Input: Article: . As the world's largest terrestrial carnivore ,the polar bear is the king of the great white north. Adult males can measure more than 9 feet in length and weigh between 770 and 1,430 pounds. The bear's body and neck are elongated, and the head is narrow and long with small, rounded ears. Polar bear populations can be found in northern Canada, Greenland, Norway and Russia, and there have been reports that polar bear tracks have been found as far north as the North Pole. The 5,000,000-square-mile range of the polar bear circles the Arctic and contains stretches of open water where seals are easily caught. Polar bears live on the annual Arctic sea ice that provides a platform from which they can hunt. They hunt seals on the sea ice by breaking into seal dens in the sea ice. The dens aren't visible from above,but seeing is less important than smelling to a polar bear -- with their keen sense of smell,polar bears can sense the breathing holes of seals in their dens beneath the snow and ice. As the southern edge of the Arctic ice cap melts in summer, polar bears are stranded on land and spend their summers fasting ,living off body fat stored from hunting in spring and winter. It might come as a surprise that this species faces an uncertain future. Climate change is causing the disappearance of sea ice from which polar bears hunt seals. Sea ice in the Arctic is melting earlier and forming later each year. With about 22,000 polar bears living in the wild,the species is not endangered at the moment, but its future is far from certain. People have reached an agreement that controls the hunting of polar bears and directs each nation to protect their habitats, but it does not protect the bears against the biggest man-made threat to their survival : global warming. If current warming trends continue, scientists believe that polar bears may disappear within 100 years.
Answer: necks

Output: Polar bears search for seals mainly through their _ .

Input: Consider Input: Article: On October 23, 2011, David Pologruto, a high school physics teacher, wasstabbed by his smart student Jason Haffizulla. Jason got straight A's and was determined to study medicine at Harvard, yet this was his downfall. His physics teacher gave Jason a B, a mark Jason believed wouldundermine his entrance to Harvard. After receiving his B, Jason took a butcher knife to school and stabbed his physics teacher. How can someone as smart as Jason do something so dumb? Studies show there is little or no correlation between IQ and emotional intelligence. During my early university years, I regarded myself as an intelligent guy. I got good marks in mathematics, physics, and other subjects. I thought such skills would surely give me a bright future. After one year of study with decent marks, I began to see two major classes of students. The first category of students turned up to few lectures, partied every weekend, enjoyed a great social life, and did minimal work to pass courses. The second category of students were intelligent and hard workers who got good grades and were very focused on their studies. Surely would these intelligent and hard-working students find the great jobs before the other lazier class of students? Not so. Students are often shocked upon graduation that their qualifications are not as important as they once thought. Graduates enter the workforce only to realize that co-workers hate them and less intelligent people are the ones receiving promotions. Educational skills are useless in some industries when interpersonal skills are absent. You can have great ideas, theories, and solve complex problems, but if you cannot effectively communicate in a persuasive and exciting manner by relating to your fellow humans, you will face an uphill battle in whatever challenges you encounter. It's not that people dislike you because of your intelligence; it's that people dislike you because you're rude and not understanding. The intelligent person with poor communication skills is insensitive or unaware of others' emotions.
Answer: he got a worse mark than usual

Output: Jason Haffizulla stabbed his physics teacher because _ .

Input: Consider Input: Article: Footracing is a popular activity in the United States.It is not only seen as a competitive sport,but also as a way to exercise,and to donate money _ .Though serious runners may spend months training to compete,other runners and walkers might not train at a11.Those not competing to win might run in an effort to beat their own time,or simply to enjoy the fun and exercise.People of all ages, from those less than one year old to those in their 80s, enter into this sport.The races are held on city streets,on college campuses,through parks,and in suburban areas,and commonly 5 to 1 0 kilometers in length. The largest footrace in the world is the 1 2-kilometer Bay to Breakers race that is held in San Francisco every spring.This race begins on the east side of the city near San Francisco Bay and ends on the west side at the Pacific Ocean.In 1 993 there were 80,000 people running in this race through the streets and hills of San Francisco.In the front are the serious runners who compete to win,and who might finish in as little as 34 minutes.Behind them are the thousands who take several hours to finish.In the back of the race are those who wear costumes just for fun.In 1 993 there was a group of men all of whom dressed up like Elvis Priestly.There was a group of firefighters who were all tied in a long line and were carrying a fire--hose .One year there was a wedding party in which the bride dressed in a long white gown and the groom wore a tuxedo .They threw flowers to by-standers,and were actually married at some point along the route.
Answer: describe a popular activity
Output: The main purpose of this text is to _ .