题目内容：

    A good disguise keeps you hidden, right? Well, sometimes the best disguise is actually the most dazzling because research reveals that flashy metallic iridescence(金属彩虹色) can visually puzzle predators, which allows colorful prey to survive another day. Those surprising results appear in the journal Scientific Reports.

Shining iridescent color, which changes depending on the angle from which it's viewed, is favored by everything from birds to beetles and blossoms to butterflies.

“And in our research group we are of course interested in why this vivid metallic color is so widespread in nature.” Karin Kjernsmo of the University of Bristol adds that in some cases the showy splashes of light are a sexual strategy. “Here I would like to point out that in some species, particularly those that display strong sexual dimorphism(雌雄两性), such as birds of paradise or some butterflies or fishes, the occurrence of iridescence is most likely driven by sexual selection. For example, in many of these cases it is the males that have these vivid iridescent colors and they use them in mate choice or they use them as a signal to attract mates.” But iridescence also shows up in situations where reproduction is not an issue. “So what we are studying now is whether natural selection imposed by predation(捕食行为) could explain the occurrence of iridescence in prey animals.”

The idea that eye­catching colors could be used as a cover­up isn't a new one.“The father of camouflage theory, Abbott Thayer, really believed that iridescence should be categorized as a camouflage strategy. And he wrote in his famous lifework Concealing­Coloration in the Animal Kingdom, already in 1909, that ‘brilliantly changeable or metallic colors are among the strongest factors in an animal's concealment’. And this sounds like a completely unreasonable thing to say, because how can colors that are both brilliant and changeable contribute to animal's concealment？”

“In a similar way, we were asking whether iridescence, due to its changeability, could work as a form of camouflage by preventing shape recognition.” Kjernsmo and her colleagues trained bumblebees to associate a particular shape—a circle or an oval—with a sugar reward. And they found that the bees, when given a choice, would preferentially visit the shape they knew to be sweet. But when the shapes were iridescent, the bees had trouble telling them apart. “It seemed that the strikingly iridescent surfaces on our targets visually broke up the otherwise recognizable shape of the targets, which made them hard to distinguish.” As for making use of this method for hiding in plain sight, “Any practical applications is of course directly linked to any industry that has an interest in camouflage, that is how to conceal objects or make them more difficult to recognize.” The researchers are currently conducting experiments with birds, which often prey on iridescent insects to see if it helps to have a bird's­eye view.

1.According to the passage, iridescence is not made use of by animals to ________.

A. live a little longer by escaping their predator(捕食者)

B. catch the attention of their mates

C. conceal themselves when in danger

D. catch sight of more colorful preys

2.From the study in the last paragraph, we can learn that ________.

A. Bees can always tell the difference between a circle and an oval

B. Bees are creatures that are fascinated by sweet things that are iridescent

C. If a circle, with a sugar reward, is iridescent, the bees may have difficulty finding it

D. Bees are likely to prefer circles to ovals, whether they are iridescent or not

3.What will be talked about in the following paragraph?

A. Whether there are any differences between bees and birds.

B. Some industries that have great interest in camouflage.

C. Why birds are not effected by iridescent insects.

D. Which camouflage theory applies more to birds.

4.Which of the following might serve as the best title of the passage?

A. A famous camouflage strategy B. Metallic iridescent as the best disguise

C. Colors unique to animals D. Shining colors as a sexual strategy