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With the completion of the Human Genome（基因组）Project more than 20 years ago, and the discovery of the double helix structure of DNA enjoying its 70th birthday last year, you might assume that we know how life works. Think again!

Evolution has a 4bn-year head start on us. However, several aspects of the standard picture of how life works-the idea of the genome as a blueprint, of genes as instructions for building an organism, of proteins as precisely tailored molecular（分子）machines and more-have wildly reduced the complexity of life. 

In the excellent book How Life Works, Philip Ball explorers the new biology, revealing life to be a far richer, more delicate affair than we have understood. Ball explains that life is a system of many levels-genes, proteins, cells, tissues, and body modules-each with its own rules and principles, so there is no unique place to look for an answer to it. 

Also, How Life Works is a much more appealing title than the overused question of "What is life?". We should be less concerned with what a thing is, and rather more focused on what a thing does. Defining a living thing implies an unchangeable ideal type, but this will run counter to the Darwinian principle that living things are four-dimensional, ever changing in time as well as space.

But it's an idea that is deeply rooted within our culture. Ball points out that we rely on metaphors（比喻）to explain and explore the complexities of life, but none suffice. We are taught that cells are machines, though no machine we have invented behaves like the simplest cell; that DNA is a code or a blueprint, though it is neither; that the brain is a computer, though no computer behaves like a brain at all.

Ball is a terrific writer, pumping out books on incredibly diverse subjects. There's a wealth of well-researched information in here, and some details that are a bit chewy for the lay reader. But the book serves as an essential introduction on our never-ending quest to understand life.

Earlier this year Rodney Smith Jr. made headlines when he drove eight hours from his home in Huntsville. Alabama, to cut the lawn for an elderly soldier in North Carolina who couldn't find anyone to help him with his yard work.

That wasn't the first time the twenty-nine-year-old Bermuda native had gained such attention. To do his good deeds, Rodney often finds leads for those in need through social media.

Back to one August afternoon in 2015, Rodney Smith Jr. was driving home. That's when Rodney saw an elderly man struggling to mow his lawn. He would take a couple of shaky steps, using the handle to stabilize himself, pause, then slowly push the mower again. Rodney decided to help. Mr. Brown thanked him greatly, and Rodney went home feeling satisfied.

Sitting at his computer to do his homework, Rodney couldn't get Mr. Brown out of his mind. There must be many Mr. Browns out there. He went online and posted that he would mow lawns for free for senior citizens. Messages flooded in.

One day a cancer-battling woman said she wasn't having a good day. Rodney decided to do more than mowing lawns. After he finished mowing, he knocked on her door. "You're going to win this fight, Madam", he said. Then he asked folks to pray for her on social media.

Word of Rodney's mission spread. A grandmother in Ohio said he'd encouraged her 12-year-old grandson to mow lawns. He got a letter from a seven-year-old boy in Kansas. "Mr. Rodney, I would like to be a part of your program, and I'll make you proud," he wrote.

That gave Rodney an idea. In 2017, he decided to establish a programme Raising Men Lawn Care Service to make a national movement for young people. The kids learn the joy of giving back.

Yard work seems like a small, simple thing, but taking care of the lawn means a lot to the people they do it for. "When we mow their yards for free, they can use the money for healthcare and food etc. It means more than you would think," Rodney said.

Recently, a 15-year-old girl Lynn Sumpter broke the rules by going to a sleepover party secretly. And her 1 gave her a choice between handing over her phone for a month, or giving them access to her social media for two weeks. She chose the latter and the netizens are so 2 of it.

Lynn Sumpter's social media 3 by her parents, Tawnya Ford and Lary Sumpter, began early in November with an instagram (照片墙) post that 4 she had chosen to abandon her social media for two weeks. So her 5 could expect "some amazing Instagram posts, snapchats and tiktoks from her parents". On November 11, Lynn's dad had already begun his 6 exploration to embarrass his teen daughter, by 7 one of his photos, saying "Felt cute. Might delete later". But that was 8 the beginning. From posing in a tight top and 9 a blonde wig (假发) to dancing around in a pair of shorts and a tank-top (背心), it seemed like there was nothing the 43-year-old wouldn't do to 10 .

Over the course of two weeks, Lynn Sumpter's Instagram following 11 from around 2,700 to 12,700 at the time of this writing, so she should probably thank her parents for their 12 punishment. The only question is "Can she 13 dad Larry's creativity?" She'll have to give it a(n) 14 as many of her social media fans are already 15 her to bring dad back.

They talk about the straw that broke the camel's back, but really it should be the password that wiped out my memory bank. 

I was going along fine -with instant recall of my bank PIN (密码)，my mobile phone number and the date of my cousin's birthday before I downloaded a gas station payment app for its new customer discount. It asked me to create a password. When I typed in "gas 1", it was rejected for not being complex enough. I tried again: "IHateHearlessOilCompanies@". But that was too long and didn't include "at least one number". But here is the thing: as soon as 1 added the fresh password into my memory, I instantly forgot all the others. My brain had hit its limit for passwords. I now know nothing. 

I had entered some passwords in a notebook. Of course, I didn't write down the actual passwords, in case it fell into the wrong hands. Instead, I masked them in a way that only a family member could figure them out. For example, I combined my bank PIN with our postal code, then added it to a list of phone numbers. It would fool even Albert Einstein.

Maybe we need a system like the one we use to remember people's names. You know, you form an association between a person's characteristics and their name by whispering "Skinny George, Skinny George" in heart after meeting them. The risk is that, upon seeing him, you'll burst out the phrase. "Skinny George" might not mind, but it's possible "Boring Betty" will. As for remembering passwords as you change them, you could simply use the first and last letters of your favorite singer's greatest hits, together with the year of their release.

Maybe I'll try that one out- -but only after describing the system in the notebook. Then I'll hide it in a place so secret that I'll never remember where it is. 

Grief ran through the first decade of my career. I photographed stories about terrible topics: immigration, conflict, war. On the cover of my notebook in 2019, I wrote, "Discover the joy again." It was intended to remind me to play more.

Sometimes I'd get a rare assignment where I could breathe — for example, photographing an article on tea for an airline magazine. I took the job hoping to make interesting, almost movie images, but at the end of the day, I found I'd made nothing of the sort. Packing up my camera, I felt like a failure.

On the drive back to the hotel, I noticed heavy steam rising from a building up ahead. Arriving at the scene, I opened the car door — and realized it was a tourist attraction traditionally pulled by a steam engine. Then, out of nowhere, a figure ran toward me. I picked up my camera and quickly made three pictures. One was out of focus. One was poorly composed. But one worked.

When I submitted my pictures to the editor for the tea article, this one wasn't chosen to be published, but I knew it meant something to me. I had been looking for good luck in my own life. This photograph symbolized exactly that.

I was 27 when I first traveled to India after the sudden passing of my father. Over many months, with my best friend, I traversed India with no phone, with limited Internet, and with healing as my compass. I climbed mountains, swam in the sea, and lived in relief entirely.

As I learned to travel to some of the world's cities with the largest population, I began to see life with more color and magic. I permitted myself to walk aimlessly, with no goal but to observe, and each moment became a dance. If this journey taught me anything, it's that what comes next will bring its own magic.

I had a terrible experience last year. One night my younger brother, Chase, was driving us home from our weekly cleaning of the church. We were both getting 1 , so we picked up a couple of energy drinks at a gas station. Then we jumped onto the freeway and 2 home.

The ride was fine. My brother was focused, so I 3 my eyes. I woke up when we were close to our exit. But the car 4 turned to the right. I did not care at first because Chase often played jokes. Then I 5 it was not a joke at all.

I shouted my brother's name at the top of my 6 . He woke up from his sleep in time to slam on the brakes, though the brakes did little to 7 us down. We crashed into a streetlight, 8 us hit the dirt hill of the off-ramp (出口匝道).

Then I 9 something white and bright shoot toward my chest. It hit me and left me breathless but 10 me from the dashboard (仪表盘). The streetlight swung around, hitting two other 11 and then crashed back onto the hood of our car. One inch 12 to us, Chase and I wouldn't be here today. A kind man 13 us out of our car, and the policeman came to 14 us. They said there were no broken ribs (肋骨) and no internal bleeding.

Our dad 15 on the scene in his car and drove us home. From that day on, we never drove while we were sleepy or tired again.