1 . There are 156 known species of glass frogs living throughout the neotropics. Recent advancements in genetics are giving researchers a revealing look into the lives of these one-inch-long tree dwellers, some of which are the size of a paper clip.

Scientists have discovered, for example, that male glass frogs in some species are stellar parents — a rare trait among vertebrates (脊椎动物). Males of at least 24 species not only protect their eggs from predators but also actively care for them. While the embryos (胚胎) develop, males of some species, such as the sun glass frog sit atop their egg clutch "like a chicken," keeping the eggs hydrated until they hatch into tadpoles (蝌蚪).

New research is also discovering how the glass frog's transparent belly forms. It's suspected that young glass frogs physically rearrange the insides of their cells and tissues to become transparent adults. Fluid between the tissue cells may also contain a substance that allows light to travel through.

Another mechanism that may allow glass frogs to blend into the green leaves on which they doze during the day is called "a biological mirror", a kind of shield or covering of crystals in many of their tissues, which reflects up to 30 percent of the light that normally reaches them. Those crystals amplify the light signal, and the frog's green looks brighter.

Many scientists studying glass frogs arc motivated by the fact that some of their subjects are disappearing—and fast. Agriculture, cattle grazing, and mining projects in the Andes are taking over the frogs' already fractured forest homes.

"As soon as they are discovered, many species are declared endangered," Guayasamin, a biologist in Ecuador, says "yet there could be an advantage in conserving such isolated ponulanons." All could be inspired to work together to set aside frog-rich patches of land as reserves, ensuring that these delicate creatures have a solid chance at survival.

2 . Many of us think of sharks as powerful, mysterious, and lonely as they move through the deep. And nowonder the fish have long been portrayed in popular media as lone predators, appearing out of nowhere to attack. But that image has come under inspection in recent years, as shark researchers around the world have discovered the fish gathering in large numbers and interacting with others of their own species in ways that are obviously friendly.

Yannis Papastamatiou, a marine scientist at Florida International University, and his team used acoustic transmitters to record the interactions over four years of about 40 reef sharks around Hawaii. Their study found that reef sharks return to the same communities year after year, forming clear preferences for sharks with some friendships that endured throughout the study. In his 2016 study, he found that individual sharks tagged with recording devices had thousands of interactions with their peers, with some pairs spending up to four straight days together. The study also found certain sharks were unmistakably companions. “These weren’t random associations,” he says.

Finding out why sharks socialize — and how much of their behavior is cooperative — is a challenge, but there are some clues, such as food availability and warmer waters. Great white sharks, are showing up in record numbers along southern California beaches as the population has doubled since 1994. While great white sharks typically maintain distances of about 30 feet from each other and don’t seem too close, they are clearly drawn together by a preference for the area. In some cases, there may not be an obvious purpose for shark’s friendship. At the Bimini Shark Lab, Smukall and his colleagues found that young lemon sharks sought out companionship of other sharks for no clear reason. There’s growing evidence that lemon sharks have their own personalities, which may influence whether they spend time with other sharks, he adds.

More would be known about the intimate lives of sharks if the field weren’t so new, due in part to a lack of funding and sharks’ negative reputation. “We’ve only had about 20 years to really start studying sharks,” says Smukall.

To their credit the four countries     1     work together in some areas（eg, the currency and international relations）, but they will have very different institutions.

England is the largest of the four countries, and for,     2     it is divided roughly into three zones. . . You find most of the population     3     in the south, but most of the industrial cities in the Midlands and the North of England. Although, nationwide, these cities are not as large as     4     as China, they have world-famous football teams and some of them even have two!

4 . Masks that helped save lives during the Covid-19 pandemic （疫情）are proving a deadly risk for wildlife, with birds and sea creatures trapped in many facial coverings in animal habitats.

Single-use masks have been found on the ground, waterways and beaches worldwide since countries required （heir use in public places to slow the pandemic's spread. Worn once, the thin protective materials can take hundreds of years to break down. "Face masks aren't going away any time soon-but when we throw them away, these items can harm the environment and the animals who share our planet," Ashley from anima! rights group PETA said.

Monkeys have been found playing with used masks in the hills outside Malaysia's capital Kuala Lumpur. And in an incident in Britain, a seagull was saved in Chelmsford after its legs got caught in an abandoned mask for a week.

However, the biggest influence is in the water. More than 1.5 billion masks made their way into the world's oceans last year, accounting for around 6200 extra tons of ocean plastic pollution, according to environmental group OceansAsia. “Masks and gloves are particularly problematic for sea creatures," says George Leonard, chief scientist from NGO. "When those plastics break down in the environment, they form smaller and smaller particles （颗粒）.Those particles then enter the food chain and influence the entire ecosystem,“ he added.

Campaigners have urged people to deal with masks properly after using them. OceansAsia has also called on governments to increase punishment for littering and encourage the use of washable masks.

5 . My work started in 2003 at my local animal shelter’s Adoption Department. It seems like such a long time ago. In the 13 years that have passed, more than 50,000 animals have passed the doors of the shelter. Most of them, I do not remember. But occasionally there are animals who stand out. Tabby was one such animal.

Tabby was one of the many homeless dogs. What’s more, she was blind and deaf. Tabby’s chances at adoption seemed remote at best. But one day a woman named Loretta came to the shelter. Her son, Gary, who suffered from epilepsy (癫痫) had seen Tabby’s picture on the shelter’s website. They were interested in meeting her! Most boys would want a puppy, a dog who could grow with him and run through grassy fields on summer days. Tabby would never be able to do that. But as they say, "love is blind". After meeting her, they decided to adopt Tabby!

If Tabby’s story had simply ended with her successful adoption, it would still have been something very special indeed but it was what happened after her adoption that some might label as "magical" or perhaps even miraculous. As Gary and Tabby did everything together, they became so "in tune" with one another that Tabby began to telegraph Gary’s seizures (疾病发作) before they occurred, giving his family a warning that one was about to strike. What’s more, Gary seemed to be having fewer and fewer seizures since Tabby’s arrival.

How could it be? There are some things that happen in this world that challenge all logic and understanding. Sometimes, the best that we can do is to accept a miraculous thing, which we didn’t attempt to explain. Because when you try to explain it, you lose the beauty and wonder of it all.