About ten men in every hundred suffer from color-blindness in some way. Women are luckier: only about one in two hundred is affected on this matter. Perhaps, after all, it is safer to be driven by a woman!

There are different forms of color-blindness. In some cases a man may not be able to see deep red. He may think that red, orange and yellow are all shades of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green — a strange world indeed.

Color-blindness in human beings is a strange thing to explain. In a single eye there are millions of very small things called "cones". These help us to see in bright light and to tell the difference between colors. There are also millions of "rods", but these are used for seeing when it is near dark. They show us shapes but no color.

Some insects have favorite colors. Mosquitoes（蚊子） prefer blue to yellow. A red light will not attract insects, but a blue lamp will. In a similar way human beings also have favorite colors. Yet we are lucky.

With the aid of the cones in our eyes we can see many beautiful colors by day, and with the aid of the rods we can see shapes at night. One day we may even learn more about the invisible colors around us.

   Cellphones, tablets, and computers are keeping children and teenagers awake at night-even when they' re not in use, according to new research. A study published on Monday in JAMA Pediatrics says that media devices are causing kids to sleep less and reducing the quality of sleep that they get. This leads to trouble of staying awake the next day.

Researchers analyzed hundreds of studies of children and teens aged 6-19. The scientists found a strong and consistent association between the use of technology at bedtime and poor sleeping. The reason is not just that kids are staying up too late with their devices. Using a computer can overstimulate the mind and emotions, the researchers say. A smartphone or tablet also gives off a light that affects the body's natural timing. These factors contribute to poor quality sleep. And many kids could be at risk. According to the study,72% of all children and 89% of adolescents have at least one device in their sleep environment. Most of these devices are used near bedtime.

"The harmful association between screen-based devices and kids' sleep is a major public health concern," the study concludes. In their conclusion, the researchers urge parents to understand the damaging influence of device use before sleep.

   Storing food is common in members of the crow family. A new study tested the birds outside for this naturally occurring behavior, which may have evolved（进化）specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to recover food. So the researchers tested whether the birds could store and recover a tool so they could use it to find their food after a gap of 17 hours — something we wouldn’t expect them to do naturally. But they were able to instantly select the tool out of a number of unnecessary items.

In another experiment, the researchers taught crows to select a token（礼品券）from a number of items so that they could then exchange it for food. Again, the birds then showed that they could plan for the future using this new behaviour. This is different from all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that chimpanzees select, transport and save appropriate tools for future needs.

These studies have shown that animals can plan for the future — but they leave an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviour.

But the new research provides the first evidence that animal species can plan for the future using behaviour that doesn’t typically occur in nature. This supports the view that at least some recognitive（认知的）abilities in animals don’t evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviour flexibly across problems in a similar way to humans. We need to study how flexible behaviour evolved. Then we might be able to see how crows’ ability to plan for the future fits in with their broader cognitive powers.

Global warming could make humans shorter, warn scientists who are said 【小题1】（find）evidence that it caused the world’s first horses to shrink nearly 50 million years ago.

In fact, a team from the universities of Florida and Nebraska says it has found a link between the earth 【小题2】（heat）up and the size of mammals — horses. The scientists used fossils to follow the evolution（进化）of horses from their earliest 【小题3】（appear）56 million years ago.

“As temperatures went up, 【小题4】（they）size went down, and vice versa; at one point they were as small as a house cat,” said Dr. Jonathan Bloch, curator of the Florida Museum of Natural History. The scientists say that the current warming could have the same effect 【小题5】 mammals — and could even make humans 【小题6】（small）.

Horses 【小题7】（start）out small, about the size of a small dog like a miniature schnauzer.【小题8】 is surprising is that after they first appeared, they then became even smaller and then dramatically increased in size, and that 【小题9】（exact）agrees with the global warming event. “It had been known that mammals were small when it was warm,【小题10】 we hadn’t understood that the temperature really was driving the evolution of body size,” Dr. Bloch said in the Science journal.

Jumping spiders (跳蛛) are vital for agricultural pest control, and 【小题1】 species can even learn to distinguish (辨别) the color red in their prey (猎物), a 2015 study 【小题2】 (show). They are able to learn to associate this color 【小题3】 poisonous prey and avoid it or find out high-quality prey.

Jumping spiders will eat almost any small pest, 【小题4】 (range) from caterpillars to flies. Not only does this 【小题5】 (natural) reduce the amount of agricultural damage from insect pests, but it means farmers can avoid using chemical treatments 【小题6】 (protect) their crops.

In total, a large number of jumping spiders, over 5,000 species, 【小题7】 (find) on every continent except Antarctica by now. Being able to adapt to the environment is a key evolutionary skill. Since the spiders are able to distinguish 【小题8】 foods are nutritious, from those that are 【小题9】 (harm). They can stay alive longer and manage a wide 【小题10】 (various) of pests.