A、The melting of the polar iceberg. B、The illegal hunting of animals. C、The disturbance of human activity. D、The pollution in th

In its natural habitat, the sun bear spends over 80% of its active waking time in daylight.
    But when disturbed by human activity, that changes dramatically. In areas where people are pushing into the sun bear’s domain, the animals are spending 90% of their waking time after dark, according to a study published in June in the journal Science.
    The study found that human activity is driving lots of mammals to shift their activity from the day into the dark hours of the night.
    Human activity of all sorts had an impact, including fatal activity like hunting as well as agriculture and land development, harvesting local natural resources, and even hiking or walking through wild areas.
    The study authors warn that profound shifts in the natural behaviour patterns of so many species disturb predator-prey dynamics that have evolved over generations, leading to unknown and potentially huge effects on the environment.
    "We really don’t know," says lead author Kaitlyn Gaynor of UC Berkeley. "Entire ecosystems might be reshaped by this behaviour. "
    Questions 1 and 2 are based on the news report you have just heard.
    1. What makes sun bears become night owls?
    2. What does Kaitlyn Gaynor say about the behaviour pattern shifts of so many species?