2 . On Christmas Eve, a team of reindeer (驯鹿) will help Santa Claus deliver gifts to children all around the world. The reindeer, led by their fearless leader Rudolph, won’t be the only ones doing something special. Back in the highest Arctic, their cousins have a remarkable ability changing their eye color.

During the summer months, when the days are long and the sun is bright, reindeer’s tapetum lucidum (荧光膜), a mirror-like layer at the back of their eye, appears golden, which helps bounce the majority of light off the eyes, effectively acting like a pair of natural sunglasses. As winter comes, and the days become shorter and darker, the tapetum lucidum turns blue to absorb more light, allowing reindeer to improve their night vision and see clear in low light conditions.

With these adaptations, reindeer can adapt and thrive in one of the harshest environments on Earth. Unlike humans, reindeer can see well into the shorter Ultra Violet (UV) range. This UV vision enables them to spot food and predators more effectively in the snowy landscape. Lichens, a key part of their winter diet, absorb UV, so they show up dark against UV-reflecting white snow. Wolf and polar bear fur also absorb UV, so instead of disappearing against snow they pop out in high contrast, allowing reindeer to spot potential threats from a distance.

Reindeer change their eyes by adjusting their tapetum lucidum, which is made of collagen fibers. In winter, the collagen fibers become packed tighter, causing the tapetum lucidum to mainly reflect blue light. This change happens when reindeer dilate their pupils (瞳孔). In summer, the reindeer’s pupils return to a smaller size, which helps reindeer reduce the amount of light entering the eye.

But their unique adaptation may hurt them. Today, the increasing use of artificial lighting, especially during the winter months, poses a potential threat to their sensitive eyes. It can make reindeer lose their way, affecting their ability to survive in their challenging environment. So it is crucial for us to be mindful of our use of electricity and make efforts to minimize light pollution to ensure the well-being and survival of these magnificent creatures.

3 . Recycling in general can be an effective way to reuse natural material resources. The U.S.’s high recycling rate of paper, 68 percent, has proved this point. But although some materials can be effectively recycled and safely made from recycled content, plastics cannot. Plastic recycling does not work and will never work.

The problem with recycling plastic lies not with the concept or process but with the material itself.   There are thousands of different plastics, each with its own characteristics. They all include different chemicals that cannot be recycled together, making it impossible to sort the trillions of pieces of plastics into separate types for processing. What’s more, plastic recycling costs more than new plastic because collecting, sorting, transporting, and reprocessing plastic waste is very expensive.

Despite this obvious failure, the plastics industry has begun a decades-long campaign to keep the lie that the material is recyclable, which reminds the public of the tobacco industry’s efforts to tell smokers that filtered (过滤的) cigarettes are healthier than unfiltered cigarettes.

Traditional mechanical recycling, in which plastic waste is ground up and melted (熔化), has been around for many decades. Now the plastics industry is promoting the benefits of so-called chemical recycling, in which plastic waste is broken down using high heat and turned into a low-quality fossil fuel. In 2018, Dow Chemical claimed that the Renewlogy chemical-recycling factory in Salt Lake City was able to reprocess mixed plastic waste through the “Hefty EnergyBag” program and turn it into diesel fuel (柴油). As Reuters showed in a 2021 survey, however, the pyrolysis (高温分解) process was not worth it.

We’re not making a case for hopelessness. Just the opposite(相反的). We need the facts so that individuals and policymakers can take action. Proven solutions to the plastic-waste and pollution problems exist and can be quickly copied across the country. These solutions include placing bans on single-use plastic bags and unrecyclable single-use plastic food-service products, and installing dishwashing equipment in schools.

Consumers can put pressure on companies to stop filling store shelves with single-use plastics by not buying them and instead choosing reusables and products in better packaging. And we should all keep recycling our paper, boxes, cans, and glass, because that actually works.