【单选题】For hundreds of years, pearl divers have gathered pearls directly from mollusks on the seafloor. This is an extremely risky profession, exposing the divers to risks of drowning, air embolism, and shar...
A.
Shark attacks on pearl divers have decreased steadily over the last three decades because of declining shark populations.
B.
Cultured pearls are generally considered more beautiful than those made by artificial means.
C.
Robotic pearl harvesters can gather pearls faster and at less cost than human divers, although they may disturb aquatic communities.
D.
Part of the value of cultured pearls derives from the exotic way in which they are obtained.
E.
With the proper equipment and training, a diver employing scuba gear can harvest three times as many pearls per hour as can a free air diver.
【简答题】In 194the US anthropology student concluded that the Siriono Why did the divers perform. less well in colder conditions? A.They were less able to concentrate. B.Their body temperature fell too quickly...