How is it that a fly always seems to be buzzing around your food moments after you sit down for an outdoor meal?

The answer is practice. Or, more specifically: evolution（进化）. Flies and other insects have been on a multimillion-year journey of evolution, improving their ability to detect food. Being able to zero in on nutritious meals is a matter of life and death.

The family of flies that I study — the blowflies — are the buzzing ones that are usually a beautiful metallic blue, with bronze and green colors. They've perfected their ability to quickly sense the smells that naturally come off picnics and garbage cans. There is a lot of competition for a resource like an overflowing garbage can because of how nutritious garbage, with the meat rotting in it, is. But the blowflies can sense these smells long before their competitors or people can, and tend to show up to the scene first.

Sensing systems differ depending on the insect and species. The blowflies' main sensing organ is their antennae, two thin projections（凸起） from the head that are covered in tiny hairs. These fine hairs are made up of special cells that contain receptors（受体） for specific smells. Think about a batch of chocolate chip cookies fresh from the oven. You can detect their delicious smells because we humans have receptors on the surfaces of the cells that line the inside of our noses. These receptors send signals to the brain: yummy food ahead. They're detecting the sweet smell of sugar-based molecules, an energy-rich food source for us.

What's a "good" or a "bad" smell can differ depending on the animal doing the smelling. The attractive rotting meat stench（恶臭） that a fly finds delightful is perceived quite differently by a person passing by an unpleasant garbage can on a hot day. But any fly that can detect the useful smell signal, which means "nutritious fly food here", will have an advantage. Over time, the insects that have the receptors for those smells will have better survival rates and produce more generations.

The best ideas are often so smart, so simple and so clearly needed; it's strange to discover they don't already exist. So it is with Farm My School, a program that's turning underused land at secondary schools into commercially achievable, regenerative market gardens farmed by and for local communities.

Co-founded by permaculturist Ben Shaw and regenerative educator James McLennan, Farm My School connects local people and organizations through volunteering that helps establish a school's market garden. Students learn about community networks, healthy eating, ecological responsibility, waste reduction, and climate relief while helping with food production. Schools integrate all these into their courses while producing vegetable boxes every week that feed local families, supply the school's food needs and ultimately pay the farmer's salary.

Farm My School has gained the extraordinary enthusiasm of the locals, who answered an online shout-out to buy tickets to the program's launch event at Bell Secondary School last October. Called Build A Farm in a Day Festival, the event featured workshops by Ben and James to share the skills required to build what they say is the world's largest no-dig garden. "It was such a powerful event, and I think that comes down to people wanting to act now," says James. "We charged for the experience and 600 guys turned up! They didn't even need free drinks to get excited. We were gardening till midnight. It was amazing. We've got true community buy-in."

Volunteers have since begun beneficial planting throughout the school. Next steps include further discussions with local communities, employing a farmer, and bringing in a teacher to develop courses. "We've seen this huge push towards seeing schools as regenerative spaces, not just for planting but for kids to be more connected to the outside world, and really seeing the school in a whole new light," James says. "For us, the big excitement is that by allowing a professional farmer to take the responsibility of growing food, it's not only on the school to look after that farm anymore, which eventually makes it much more sustainable," adds Ben.

On September 9,senior Andre Samaraweera qualified as a semifinalist(进入半决赛选手) for the National Merit Scholarship. In the spring, Andre will find out if he has qualified for the finalist position. "Seeing my score on the PSAT was by far the most exciting because it felt pleasant to see all my hard work pay off," Andre said. "I was happy that I could qualify to get a scholarship because of my academic scores."

The National Merit Scholarship is one awarded to those who do well on the Preliminary SAT or the National Merit Scholarship Qualifying Test. The National Merit Scholarship Corporation will grant around 7,600 students the scholarship after an intense filtering of about 1. 6 million entries.

"The most difficult part of the PSAT was actually having to study," Andre said. "I had to force myself to actually study, because I knew if I didn't, I wouldn't do well and would probably not make as high of a score as I had."

Andre took the PSAT his junior year and got a 1450/1520 and missed three questions in English and made a perfect score on the math portion.

As a semifinalist he has already passed multiple stages in the selection process and now competes with only around 16,000 students for scholarships.

The first scholarship opportunities are single-payment scholarships worth $2,500; the second scholarship is a corporate-sponsored one which is for finalists with career plans the sponsor wishes to encourage. Finally there is the college-sponsored scholarship which is where officials of each sponsor college select winners of their awards from finalists who have been accepted for admission.

"It's just a PSAT. The real SAT has a lot more impact on my future," Andre said. "It's not hard to know everything for the PSAT; the difficulty lies in applying everything perfectly."