Every year gray whales swim a 10,000 miles round-trip, from the cold waters near Alaska, down the coast of North America to the warn waters near Mexico, and back again. It is one of the longest migrations (迁徙) of any mammal (哺乳动物).

    All day, all summer long, in the cold waters near Alaska, gray whales eat and eat.

    Instead of teeth, gray whales have baleen (鲸须) they use to get food from ocean water. They get big mouthfuls of muck (淤泥) from the ocean floor, then push that muck right back out through their baleen. The mucky water flows through, but tiny animals get trapped in the baleen and licked up.

    When the water starts to freeze, the whales begin their long trip south. They swim night and day, without stopping to eat or rest. During the long journey, migrating whales may push their heads out of the water to see where they are.

    Two months later, the whales reach Mexico. Babies are born here in warm, shallow (浅的) waters called lagoons (濒海湖). Ocean lagoons have no food for the adults, but the babies are safer here than in the open seas. All winter the babies grow big and strong.

In spring first the dads and teenagers leave the lagoons, then the moms with babies. Migrating gray whales swim close to shore, especially moms with babies. The ice is melting up (融化) north, and it's time for the hungry whales to make the long journey back to their summer feeding grounds.

    Simone was born in Ohio, but grew up in Texas. Early on, she and her siblings (兄妹) were adopted by her grandparents, who she says support her in everything. She first realized she wanted to be a gymnast at the age of 6 when she and her classmates went on a field trip to a local gym. A coach at the gym saw her natural talent and wrote a letter to her grandparents urging them to get her involved. The sport she signed up for “for fun” soon turned into her life's enthusiasm.

    Simone is energetic, so it's no surprise that she's got a few medals in her time. Her ten world gold medals are the most ever achieved by a woman in gymnastics history. She is also the first woman to win four medals at the same World Championships, which happened in her second year performing in 2014.

In 2015 Simone became the first gymnast to win three constant all-around titles at the World Gymnastic Championships. She even amazed herself, telling the interviewer “I blew my own mind.” and posting to social media “breaking history is kind of cool.”

    What surprised everyone most though, was that she was performing perfectly as she usually does—her skill is so beyond everyone else that she can't be beaten even when she trips up!

    Women are friendly. But men are more competitive. Why? Researchers have found it's all down to the hormone oxytocin （荷尔蒙催生素）. Although known as the love hormone, it affects the sexes differently.

    "Women tend to be social in their behavior. They often share with others. But men lend to be competitive. They are trying to improve their social status," said Professor Ryan.

    Generally, people believe that the hormone oxytocin is let out in our body in various social situations and our body creates a large amount of it during positive social interactions （互动） such as falling in love or giving birth.

    But in a previous experiment Professor Ryan found that the hormone is also let out in our body during negative social interactions such as envy.

    Further researches showed that in men the hormone oxytocin improves the ability to recognize competitive relationships, but in women it raises the ability to recognize friendship.

    Professor Ryan's recent experiment used 62 men and women aged 20 to 37. Half of the participants（参与者）received oxytocin. The other half received placebo （安慰剂）.

    After a week, the two groups switched with participants. They went through the same procedure with the other material.

    Following each treatment, they were shown some video pictures with different social interactions. Then they were asked to analyze the relationships by answering some questions. The questions were about telling friendship from competition. And their answers should be based on gestures, body language and facial expressions.

    The results indicated that, after treatment with oxytocin, men's ability to correctly recognize competitive relationships improved, but in women it was the ability to correctly recognize friendship that got better.

    Professor Ryan thus concluded: "Our experiment proves that the hormone oxytocin can raise people's abilities to better distinguish different social interactions. And the behavior differences between men and women are caused by biological factors （因素） that are mainly hormonal. "

    After a morning hike in the Saneum HealingForest, 46-year-old firefighter Kang Byoung-wook has tea made from the bark of an elm tree, practices yoga (瑜伽), and makes a picture with dried flowers. He is one of 40 firefighters taking part in a three-day program, the aim of which is to offer "forest healing" (森林治愈); the firefighters all have posttraumatic stress disorder (创伤后应激障碍).

    Saneum is one of three official healing forests in South Korea. Soon there will be 34 more. South Koreans-many of whom suffer from work stress, digital addiction, and great academic pressure have accepted the medicalization of nature with great enthusiasm.

    There is increasing evidence that being outside in a pleasant natural environment is good for us. But how many of us get to enjoy nature regularly? Fewer and fewer, it seems. According to Lisa Nisbet, a psychology professor at Canada s Trent University, evidence for the benefits of nature is pouring in at a time when we are most disconnected from it.

    "We don't think of being outdoors as a way to increase happiness," says Nisbet. "We think other things will, like shopping or TV." But South Korea is starting to challenge this opinion.

    So what are some of the benefits of nature that Nisbet refers to? Being surrounded by nature has one obvious effect: It calms us and reduces our stress levels. This has been shown to lower blood pressure and heart rates.

    Another experiment conducted by psychologist Stephen Kaplan found that people who took a 50-minute walk in a park had better attention and short-term memory than those who took a walk along a city street.

    Perhaps what's more surprising is that nature may also make us more creative. David Strayer, a psychologist at the University of Utah, showed as much with a group of participants, who performed 50 percent better on creative problem-solving tasks after three days of wilderness backpacking.

    In fact, we may never know exactly what nature does to the brain. Something mysterious will always remain, and maybe that's as it should be.

    Many high school students consider a college education useless. Therefore, they choose not to go to college. If you're one of them, think again. Here are some reasons why you should go to college and receive a good education there.

    Schools and universities are the first sources of knowledge. We take that knowledge later on to build our careers after graduation. More knowledge will be gained after you start working, but without an education, that job will not be within easy reach. Knowledge leads to knowledge.

    While limited within the walls of the educational institutions, we openly explore other cultures of the world. We come to know that ours is not the only culture. Other cultures have valuable insights to share, enriching our own Education also makes us want to travel and interact with various cultures, broadening our horizons.

    When there's a downturn in the economy, those who attended college will be more likely to find a new job than those who only finished grade school and have a limited skills set. The more education you have, the more chances you will get to improve the quality of your life as you have a better job and earn a higher salary.

    When you're skillful and knowledgeable, you get to "rub knees" with people of similar backgrounds and tastes. It means a good education leads to excellent networking. Good networking can benefit you a lot in your later life.

    A good education makes you a more interesting person. You can talk about ideas and events instead of just other people and what's on sale in stores. An educated person doesn't gossip, having a preference to discuss ideas and listen to what other people have to say.

More than 100 scientists traveled to faraway places to collect wild crop seeds in an effort to help battle climate change. The scientists have been likened to the hero of the Indiana Jones movies. Like him, they had to face blood-sucking creatures and fierce tigers. Some-times, they had to use elephants for transportation because they couldn't find any other means of transportation.

A report on the project was published last week. It described the results of a six-year search to collect thousands of wild seeds. The seeds could be important in feeding a growing human population at a time when rising temperatures are affecting crop production in some areas.

The scientists traveled on foot, by four-wheeled vehicles, boat and riding horses and they even rode elephants to reach faraway areas. They collected 4,644 seed samples of 371 wild relatives of 28 crops. Many of those wild relatives are said to be endangered.

The Crop Trust, a nonprofit organization that works to save different kinds of crops, was directing the project. The group was working in partnership with Britain's Royal Botanic Gardens and Millennium Seed Bank. Additional financial support came from Norway. The project is believed to be the largest organized international effort yet to collect and protect crops' wild relatives.

Some relatives of widely grown crops have developed so they can survive usual and severe conditions such as low rainfall, flooding, extreme temperatures and poor soils. Scientists say the wild crops offer a largely unused source of diversity for protecting crops against climate change.

Some crops are threatened because of destruction of forests, conflict and expanded cities. Experts say losing this diversity could endanger food security around the world. A United Nations report says that food supplies are under severe threat. The report notes that the number of animal and plant species are quickly disappearing as the world deals with how to feed a rising population.