Question: Read the following article and answer the question. Article: Humans: It's time to give up the earth or face extinction . It could be the plot of a summer blockbuster , but this prediction isn't science fiction. It's a glimpse  of the future, according to famous British scientist Stephen Hawking. "I see great dangers for the human race," he said in an interview with global forum  Big Think. "There have been a number of times in the past when its survival has been a question of touch-and-go." Hawking, an award-winning physicist, says humans must evacuate our home planet within the next two centuries and expand into space to survive. "I believe that the long-term future of the human race must be in space," he said. "It will be difficult enough to avoid disasters on our planet in the next hundred years, let alone the next thousand, or million." Hawking, who was awarded the Presidential Medal of Freedom last year, has recently voiced many concerns about the future of life on the earth. In April, he spoke about his fear of aliens in an interview for the Discovery Channel. "If aliens visited us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans," he said. "Such advanced aliens would perhaps become wanders, looking to conquer and colonize whatever planets they can reach."  But Hawking says he is still hopeful for the future of humanity. "I'm an optimist," he told Big Think. "We have made remarkable progress in the last hundred years. But if we want to continue beyond the next hundred years, our future is in space." Getting to another planet will prove a challenge, not to mention colonizing it for humanity. University of Michigan astrophysicist Katherine Freese told Big Think that "the nearest star to the earth is Proxima Centauri which is 4.2 light years away. That means, if you were travelling at the speed of light the whole time, it would take 4.2 years to get there--or about 50,000 years using current rocket science." Question: Hawking's attitude towards the future of humans is   _  . Answer:
Answer: positive

Question: Read the following article and answer the question. Article: Even bird brains can get to know an entire continent ----- but it takes them a year of migration to do so, suggests a Princeton research team.    The scientists have shown that migration adult sparrows can find their way to their winter nesting grounds even after being thrown off course by thousands of miles.    The team first brought 30 sparrows to Princeton from northern Washington State, where the birds had been in the process of migrating southward from their summer breeding grounds inprefix = st1 /Alaska. Half the birds were juveniles  of about three months in age that had never migrated before, while the other half were adults that had made the round trip to their wintering site in the south-western United States at least once.    After the birds were released, they attempted to resume  their migration, but both age group grew disoriented  quickly.    "All the birds scattered  at first," Wikelski said. "It was clear that they were turned around for a couple of days. But while the adults eventually realized they had to head southwest, the younger birds resumed flying straight southward as though they were still in Washington."    "The adults," said team member Richard Holland, "recovered their bearings because they possess something the younger birds do not, which is an internal map."    "These birds need two things to know where they are and migrate effectively: a 'map' and a 'compass'," saidHolland, a postdoctoral research associate in Wikelski's lab. "What we've found is that juveniles use their compass, but the adults also use their map."    Hollandsaid, "The birds do not lose the compass as they age, but somehow develop the map, eventually applying both tools to keep on track during migratory flights. Scientists already have determined that the compass is based on the sun or the magnetic field, but where the map comes from remains a mystery----one that the team will be exploring in coming years." Question: Scientists are still not sure   _  . Answer:
Answer: what a 'map' is based on

Question: Read the following article and answer the question. Article: When Juliet was a child, she often went to the city park and played with her friends. On a sunny morning, when Juliet came to the park with her mum, she looked around and felt very unhappy. "What's the matter, dear?" asked her mum. Juliet replied, "Mum, there's so much trash on the ground." Juliet's mum looked around. There was paper, boxes and glass bottles everywhere. "What can we do?" asked Juliet. "I'm sure you will think of something," said her mum. As soon as Juliet and her mum went home, Juliet painted a picture of the park and wrote a sign in large black letters at the top of the picture. The sign read "PLEASE KEEP OUR PARK CLEAN". Later, she took plenty of bags and went back to the park with her mum. Juliet put up her picture on a big trash can  . "Will you help me pick up the trash, Mum?" Juliet said as she handed her mum a bag. "I sure will," replied her mum. The children at the park ran over to see what was going on. Juliet handed them each a bag. "Let's clean this place up," said Juliet. Then they began to pick up the trash, talking and laughing. Soon all the bags were full. "We need to come back another day. There's still some trash on the ground, but the park looks much better," said Juliet. Her mum said, "So it does. _ " Question: Juliet put up the picture to   _  . Answer:
Answer: