阅读理解
If you were looking for an animal to take the title of 'most violent fish in the sea', then the puffer
fish(河豚) would have to be a strong competitor.Not only is it poisonous-though that doesn't stop
people trying to eat it-and able to scare off other creatures in the sea by inflating itself to become much
larger than normal, but also it chews on its own brothers and sisters when it is young.
Puffers attach their eggs to rocks near the bottom of the sea, often at the mouths of bays.Then the
larvae(幼鱼)move to the wide part of the river once they have grown a little.Having put on more
weight, they head for the sea.It's no childhood for the puffer fish, though, as Shin Oikawa and his
colleagues found when they hatched puffer larvae in the lab and monitored them for two months.They
found the larvae went through three step changes when they reached body weights of 0.002 grams,
0.01g and 0.1g.When a larva went through one of these changes, its behavior also changed.For instance,
once a larva passed the first level it would grow its first teeth and could start attacking the larvae that had
not reached that stage.Similarly, any larva that had reached the 0.01g or 0.1g levels would start attacking
the larvae that hadn't.
The baby fish had a 'relatively small mouth', so rather than swallow their brothers and sisters whole,
they would bite pieces out of them.Despite this limitation, the fish caused plenty of deaths.
Eat one puffer and the poison will paralyze your muscles, including the muscles responsible for breathing
－so death is usually caused for lack of oxygen.Famously, the fish is a delicious dish in Japan, where
highly qualified chefs produce dishes that contain safe levels of the poison.The puffer does not go to the
trouble of producing poison itself.Instead, it hosts bacteria that combine the poison.It obtains these
bacteria from its diet, so the youngest fish are not poisonous.

1. The following statements account for the violence of puffers EXCEPT ________.
A. they often pr people from capturing them
B. they can become larger to frighten enemies away
C. they kill their younger companions after growing older
D. they can poison people who try to eat them

2. We can learn from the second paragraph that the puffer ________.
A. can mostly grow to the weight of 0.1g gram
B. never changes its behavior as it grows
C. often finds safe places to have its next generation
D. begins to grow teeth when it reaches the second level

3. Where does the poison in the puffer's body come from?
A. Its inner organism.
B. The chemicals in the water.
C. The diet it eats.
D. Small fish around it.

4. It can be inferred from the last paragraph that ________.
A. the puffer does produce poison all by itself
B. people like eating puffers though they are poisonous
C. people can eat the puffer prepared by themselves
D. fishermen often capture the youngest puffers