FOR us humans， one of the greatest experiences is to taste all kinds of delicious food． But for penguins， they cannot get a taste of this happiness． That's because penguins can't actually taste the delicious flavors （味道） of their favorite food-fish!
Scientists from the University of Michigan examined the genome （基因组） of five species of penguins． They found that not one can taste umami （鲜味）， the flavor of meat or fish， the BBC reported．
Many animals have five basic tastes： sweet， sour （酸）， salty bitter （苦） and umami． But according to genetic（遗传的）data， penguins are believed to have only sour and salty tastes．
These findings are surprising and puzzling． And scientists don't have a good explanation for them． But they have a few ideas．
First， one of the umami genes doesn't work in cold temperatures． "It's about zero degrees when they eat cold fish，" Zhang Jianzhi， the lead scientist， told the Daily Mail， so even if the penguins had a functional（功能的）gene， it might not work when they needed it．
Plus， penguins' tongues are very special which may have something to do with their lack of taste． Instead of being covered with taste buds which help to taste food， penguins' tongues are extremely spiky （钉子似的）． This is better for them to hold slippery （滑的） fish than tasting them． One study even showed that some types of penguins don't even have taste buds．，
But penguins seem to be managing just fine．
"Their behavior of swallowing food whole and their tongue structure and function suggest that penguins need no taste perception（知觉），" said Zhang．
1. The study finds that ______ ．
A. different penguins have their own favorite fish
B. penguins have different genomes for the five tastes
C. penguins can't taste the flavor of fish
D. penguins don't have any of the five basic tastes
2. Penguins can only taste ______ ．
A. salty and sour B. sour and sweet
C. sweet and salty D. bitter and umami
3. From Paragraph 5， we learn that ______ ．
A. penguins' umami genes work well in cold temperatures
B. penguins only eat cold fish
C. temperatures can decide the umami genes of penguins
D. the umami genes in penguins would work when needed
4. Paragraph 6tells us that ______ ．
A. a lack of taste is good for penguins
B. penguins' tongues are very spiky
C. penguins prefer to eat slippery fish
D. there are no taste buds on penguins' tongues
5. All of the following decide that penguins need no taste perception EXCEPT ______ ．
A. they always swallow food whole
B. their tongue structure is special
C. their tongue function is different
D. they live in cold temperatures
