Turtles have an unfortunate habit of eating plastic objects floating in the sea.These then cannot be digested，and may ultimately kill them.It is widely assumed that this fondness for plastics is a matter of mistaken identity.Floating plastic bags，for instance，look similar to jellyfish （水母），which many types of turtles love to eat.Yet lots of plastic objects that end up inside turtles have no similarity to jellyfish.Joseph Pfaller of the University of Florida therefore suspects that the smell of marine microorganisms （海洋微生物） which grow on floating plastic objects fools turtles into feeding.
   Researchers at the University of California noticed that certain chemicals，which are released into the air by floating plastics，are those which many seabirds sniff（嗅） to track down food.These chemicals mark good places to hunt because they indicate plenty of the algae （海藻） and bacteria.The researchers also found that birds which pursue their food in this way are five or six times more likely to eat plastic than those which do not.Since turtles are known to break the surface and sniff the air when finding the way to their feeding areas，Dr.Pfaller indicated that they are following these same chemicals，and are likewise fooled into thinking that floating plastic objects are edible.
   To test that idea，he and his colleagues set up an experiment.They arranged for 15 turtles，each around five month old，to be exposed，in random order，to four smells：the vapor from deionised water（去離子水）；the smell of turtle-feeding meals；the smell of a clean plastic bottle；and the smell of a bottle that had been kept in the ocean for five weeks to allow algae and bacteria to grow on it.Two of the smells - the smell of meals and that of five-week-old bottles proved far more attractive to the animals than the others.
   On the face of it，the turtles were responding to the smell of old bottles as if it were the smell of food.Actually，in an unpolluted ocean，anything which had this smell would indeed be edible - or，at least，harmless.However，unfortunately，five-week-old plastic bottles and their like are not.

（1）Paragraph 1 mainly tells us that turtles

B

B

.
A．mistake plastic objects for jellyfish
B．are fooled into eating plastics by a smell
C．are dying out as a result of plastic pollution
D．break down plastics without much difficulty
（2）What can we infer from the research on seabirds？

D

D

A．Seabirds eat plastics for the taste.
B．The algae and bacteria grow well on plastics.
C．Seabirds prefer being fed with jellyfish like turtles.
D．Some seabirds pursue food in a similar way to turtles.
（3）What does the underlined word "edible" in paragraph 3 mean？

A

A

A．Fit to eat.
B．Pleasant to smell
C．Far to reach.
D．Easy to digest.
（4）What is the function of the last paragraph？

C

C

A．To explain why the ocean is polluted.
B．To show his agreement on the research findings.
C．To arouse the awareness of protecting the ocean.
D．To call on people to feed the turtles with proper food.