人体细胞是有寿命的，每天都在更新，衰老死掉的细胞会被新的代替。
全身的细胞全部替换掉，需要经过七年，也就是在生理上，我们每过七年就拥有一个新的身体。
细胞的更替是循序渐进的，并不会在同一时刻全部换掉，不同的细胞代谢的时间和间隔都不同。
人的大脑细胞是永久不变的，所以，就算身体经过了七年的更新周期，你的脑子依然还是同一个。

你不知道的 有趣知识分享

人体的细胞几年就会更新 一次？

The European Union (EU) has encouraged citizens across the continent to stockpile food, water and other essentials to last at least 72 hours as war, cyberattacks, climate change and disease increase the chances of a crisis.

The call to action for the EU's 450 million citizens comes as the 27-nation bloc rethinks its security, especially after Donald Trump's US administration warned that Europe must take more responsibility for it.

In recent years, the EU has been forced to deal with the coronavirus pandemic, and the threat from Russia, including its attempts to exploit Europe's dependence on its natural gas to weaken support for Ukraine.

NATO Secretary-General Mark Rutte has warned that Russia could be capable of launching another attack in Europe by 2030.

"Today's threats facing Europe are more complex than ever, and they are all interconnected," said Preparedness and Crisis Management Commissioner Hadja Lahbib as she shared a new strategy for dealing with future disasters.

While the commission is keen not to be seen as alarmist, Lahbib said it's important "to make sure people have essential supplies for at least 72 hours in a crisis." She listed food, water, flashlights, ID papers, medicine and radios as things to stock.

Lahbib said the EU should build up a "strategic reserve" and stockpile other critical resources including firefighting planes; medical, energy and transport equipment; and specialized assets against chemical, biological and nuclear threats.

The EU's plans are similar to those in France, Finland and Sweden.

Last year, Sweden updated its civil emergency advice "to better reflect today's security policy reality" such as what to do in case of nuclear attack.

Not all EU countries have the same level of crisis preparedness, and the commission also wants to encourage them to coordinate better in case of emergency.

President of the European Commission, Ursula von der Leyen, said: "New realities require a new level of preparedness in Europe."



Practice Listening, Reading & Comprehension

EU Asks People to Gather Supplies in Case of Crisis

The number of couples getting married in South Korea increased by almost 15% between 2023 and 2024.

That's the biggest percentage increase in marriages since the government began collecting this data in 1970.

More than 222,000 couples got married in South Korea in 2024. That's good news for a country with one of the world's lowest birth rates.

The government has been trying to encourage people to get married and have children to help boost the country's shrinking population.

It may just have worked. However, not all young people are convinced that marriage is the right thing for them.

According to The South China Morning Post, many young people in the country are still choosing an "unmarried lifestyle" for personal and financial reasons.

Some said that getting married and doing things like buying a home and having children are too expensive.

Others felt they would be more likely to find happiness on their own.

The government data also showed that the number of marriages between South Koreans and foreign nationals has increased for the third year in a row.

There were almost 21,000 of these marriages last year. That's an increase of more than 1,000 from 2023, although still not quite as high as it was before the coronavirus pandemic.

Almost three out of 10 foreign husbands were from the US. And about a third of foreign wives were from Vietnam, while many others were from China and Thailand.

The number of divorces among couples of different nationalities also decreased last year, according to Yonhap News Agency.

Big Rise in Number of Marriages in South Korea

Egg prices are rising in America. The average cost of a dozen eggs hit a record $4.95 in January — up 53% from a year earlier. The price was below $2 in early 2022.

While the coronavirus pandemic and inflation have affected prices, experts say the real problem has been bird flu. An outbreak that began in early 2022 has become the largest in US history, affecting more than 100 million egg-laying hens.

To cope with rising egg prices, some Americans have been going straight to the source — and renting hens.

Rent The Chicken in New Hampshire is letting people rent egg-laying hens for six months at a time. For $595, you get two egg-laying hens and a guide on how to take care of them, as well as chicken feed and a coop to keep the birds in.

The birds actually aren't very difficult to take care of, explains Brian Templeton, owner of Rent The Chicken. "You just let them out and walk around and they go in at night on their own," he told CBS News.

"People really enjoy it," he added.

Rent The Chicken says two hens should produce eight to 14 eggs per week.

That comes to about $25 for every dozen eggs — so it's not really a savings.

You can also get four hens for $735, which would reduce your cost to about $15 per dozen eggs.

However, if you'd like to keep your chickens and coop at the end of your rental period, you can — for an extra $350 to $450.

According to the University of Wisconsin-Madison, hens will usually live for six to eight years, and produce eggs for three to four of those years.

So that might bring your price down over time.

Americans Rent Chickens as Egg Prices Rise

Hawaii's regular sunshine, short rain showers and clean air come together to create some of the planet's best conditions for viewing rainbows. Rainbows are seen so often here that a University of Hawaii professor calls the state the "rainbow capital of the world."

"Hawaii has maybe the best rainbows on the planet," said Steven Businger, professor of atmospheric sciences at the University of Hawaii at Manoa.

He has even created an app called RainbowChase to help people find rainbows in Hawaii.

Rainbows form when drops of rain refract sunlight into a spectrum of colors. The brighter the sun, the clearer the rainbow.

Hawaii's winds bring many small showers with enough blue sky between them for the sun to shine through. Conditions are best during the rainy season from October through April.

Visitors should look for rainbows when it's both sunny and raining at the same time. Rainbows will appear opposite the sun. They will seem larger and higher in the sky in the early morning and late afternoon, when the sun is lower on the horizon.

Rainbows are popular symbols of island life. Pictures of them can be seen on buildings and buses, and even on vehicle license plates.

"They cause us to stand still and for a moment, forget about the past and the future," Businger said.

There are about 20 names for rainbows in the Hawaiian language, including different words for different types of rainbows.

Sam 'Ohu Gon III, senior scientist and cultural adviser at The Nature Conservancy in Hawaii, said rainbows are considered a symbol of Kāne, one of the four main gods in Hawaiian tradition. The closer you get to a rainbow, the more likely you are to meet a supernatural force or a powerful person, he said.

A rainbow is also believed to show that an aumakua — a deified family member or family god — is nearby.

Why Hawaii Is the 'Rainbow Capital of the World'


The number of tigers in India more than doubled between 2010 and 2022, according to a new study.

In 2010, there were around 1,700 tigers in the country — but there were almost 3,700 by 2022, the study said.

The study also said that tiger numbers had increased because the animals were better protected from poachers and because their habitats were better protected too.

The researchers added that the amount of contact between humans and animals has been reduced, and the country has made sure that the tigers have enough prey.

The researchers said the results show that, with the right attitude, people can make a difference.

Some people now want the country to spend more time and money on protecting other animals too.

Of all the tigers in the world, 75% are now in India, in an area of about 138,000 square kilometers.

But many of these animals live close to large numbers of people.

The researchers said some communities have benefited from the increased tiger population because it has meant tourists have visited the area to see the animals.

However, tiger attacks on humans do happen, and with India's human population growing, this problem won't go away.

But the researchers said the number of tiger attacks per year is quite small, and many more people are killed by leopards, wild pigs and snakes, and in car accidents.

However, while many have said that the increase in tigers is good news, others are not sure about the accuracy of the data, which was collected by government-supported agencies.