62. Which of the following is the name of a play?
A. Blazing Saddles.
B. Guess Who's Coming to Breakfast.
C. Importance of deciding basic goals of the Women's Union.
D. Unskilled Labours on Rivers and Canals in Upper Canada, 1820 - 1850.
D
Fish Ears Tell Fish Tales
Fish have ears. Really. They're quite small and have no opening to
the outside world carrying sound through the body. For the past seven years,
Simon Thorrold, a university professor, has been examining fish ears, small
round ear bones called otoliths.
As fish grow, so do their otoliths. Each day, their otoliths gain
a ring of calcium carbonate(碳酸钙).By looking through a
microscope(显微镜)and counting these rings, Thorrold can
determine the exact age of a young fish. As a fish gets older, its otoliths
no longer get daily rings. Instead, they get yearly rings, which can also be
counted, giving information about the fish's age, just like the growth rings
of a tree.
Ring counting is nothing new to fish scientists. But Thorrold has
turned to a new direction. They're examining the chemical elements(元素)of each otolith ring.
The daily ring gives us the time, but chemistry tells us about the
environment in which the fish swam on any given day. These elements tell us
about the chemistry of the water that the fish was in. It also says something
about water temperature, which determines how much of these elements will
gather within each otolith ring.
Thorrold can tell, for example, if a fish spent time in the open
ocean before entering the less salty water of coastal areas. He can basically
tell where fish are spending their time at any given stage of history.
In tne case of the Atlantic croaker, a popular saltwater food
fish, Thorrold and his assistant have successfully followed the travelling of
young fish from mid-ocean to the coast, a journey of many hundreds of miles.
This is important to managers in the fish industry, who know
nearly nothing about the whereabouts of the young fish for most food fish in
the ocean. Eager to learn about his technology, fish scientists are now
lending Thorrold their ears.