Read the text below and then write down the correct answer.
BIRDS OF A FEATHER FLOCK TOGETHER -- RIGHT INTO SCIENTISTS' NETS
All pet owners will happily explain to you their dog or cat's character traits -- probably in far more detail than you ever wanted to know. But the idea of animal personality is not one that's been formally studied all that much. A new study has classed a species of bird into groups of more and less aggressive males. Researchers gauged the response of male collared flycatchers to female birds, to a strange object, and to other males. They found that each type of individual displayed consistent behaviour in each of these situations.
However, they also found that the birds more likely to take risks also were the ones most likely to be trapped -- and thus studied further -- raising important questions about the skewed sample set presented when researchers base their findings on animals caught in traps. It's kind of like when talk show hosts say "95 percent of 13-year olds (who responded to our online survey) are smoking pot!!!" -- leaving out the part about it really being 95 percent of the particular 20 teenagers who felt like responding to our survey.
1 Why is research into birds caught for research purposes unreliable?
A: Because birds caught in the wild behave differently from birds that are used to humans.
B: Because male birds are more aggressive to birds and strange objects than female birds.
C: Because researchers fail to collect a representative sample of the population.
Preservation of Wild Places May Help Protect Human Health
In eco-immunology, a young new field of scientific research, the main goal of researchers is to understand how the spread of disease in wildlife is exacerbated by human and environmental elements (like climate change). These researchers are also trying to 1_________ how deadly diseases move from animal to human populations. In the last 30 years there have been more than 300 infectious diseases that have passed from animals to humans including AIDS, Ebola and Lyme disease.
2_________ the emergence of diseases in wild populations is still not well understood, scientists have gained some new insight into this process. According to the article “In Wild Animals, Charting the Pathways of Disease” from the New York Times, when the natural habitats of a species is disturbed the resultant stress on their immune systems can lead to a 3 _________ chance that diseases could be spread to humans. This is yet another way that the disturbance and loss of wild places may 4_________an impact on human health.
Studies of bat viruses by researchers such as Jonathan H. Epstein of the EcoHealth Alliance and Dr. Plowright of the Center for Infections Disease Dynamics, have indicated that in a natural 5_________, bats spread viruses to each other over and over. In an undisturbed ecosystem this helps the bats build their immune defences.
When however, the native wild habitat of a species is replaced with cities and suburbs, the stress on a species immune systems 6_________ higher amounts of the virus to excrete in their waste. In a new environment, the virus-rich bat waste is 7_________ to new “naïve immune systems” that are unable to fight the virus. This can lead to widespread disease, 8_________ as the Hendra virus.
Researchers are learning changes in balance between diseases and the immune system can affect the 9_________web of life, or an entire ecosystem – including humans. These studies are shedding new light on the effects of human changes to wildlife habitats. Keeping nature intact and practicing sustainable development can aid in conserving not 10_________ecosystem health, but human health as well.
||C Because researchers fail to collect a representative sample of the population.