When I think about ducks. I picture my mother's pets. She saved Lucy and Fran from a very wet area when I was 16 years old. The little ducks were weak and sick. My mother helped them to get healthy.

Lucy and Fran lived in a large box in the garage. They became family pets. They were members of our family. Lucy followed me around. She quacked and quacked. She liked attention.

My brother Tim read everything he could find about ducks. He learned to care for our pets. He made sure that the box in the garage was fit for our pets. It had a heat lamp and a feeder. He gave them water and fresh straw each day. What a hit! Lucy and Fran loved their house. They quacked to say, “Thank you!”

On a rainy morning, Lucy walked near me to the mailbox. She walked so close that we knocked each other. I fell into a big mud hole. All the letters from the mailbox got wet. They were covered with muddy, brown water

What's worse. Tim watched from the window. When I got back into the house, he was on the kitchen floor holding the sides of his stomach. He laughed there.

I stomped my feet and threw up my arms. My mom calmly listened to me shout. “It's okay, honey. If you prefer to you can trade beds with the ducks!” she comforted.

With that in mind, I went to the garage and made my peace with the ducks. My own bed looked a lot better than their straw and heat lamp.

Antaretica’s ice-white environment is going green and facing other unexpected threats. Scientists say that as temperatures go up in the polar region, invading (入侵) plants and insects, including the flies, cause a major conservation threat.

More and more of these invaders, in the form of larvae (幼虫) or seeds, are surviving in coastal areas around the South Pole, where the temperature has risen by more than 3℃ over the past three decades. Glaciers have retreated, exposing more land which has been occupied by mosses that have been found to be growing more quickly and thickly than ever before-providing potential green homes for invaders.

“The common house flies are a perfect example of the problem the Antarctic now faces from invading species,” said Dominic Hodgson of the British Antarctic Survey. “It comes in on ships, where it exists in kitchens and then at bases on the continent. It now has an increasing chance of surviving in the Antarctic as it warms up, and that is a worry. Insects like the house flies carry bacteria that could have a deadly effect on native lifeforms.”

The Antarctic has several native species of insects. Together with its native mosses, these are now coming under increased threat from three major sources: visiting scientists, increasing numbers of tourists and global warming. However, it is global warming that is the main driver of the greening of Antarctica.

In 2015, more than 38,000 tourists visited Antarctica. “These tourists are often very careful about not leaving waste or having mud. But they could carry seeds or larvae on their boots when they set foot on the Antarctic,” said Hodgson.

More and more invasive insects and plants have been found on the Antarctic and have required removal. “the insects and plants that are native to Antarctica have survived these for thousands of years,” said Hodgson. “We have got to act now if we want to save the environment.”

If you’ve ever thought that dogs seem to know when people are stressed, you were right. Scientists in Ireland ran an experiment which showed that dogs can tell the difference between the smell of a person when they’re relaxed and when they’re stressed.

Researchers at Queen’s University Belfast, led by scientist Clara Wilson, worked with four dogs. They taught the dogs to use a special smell-testing device with three openings. The scientists used treats and rewards (奖励) to train the dogs to find and signal the correct opening. Over time, the dogs were given harder and harder smelling jobs. The final goal was to see if they could smell stress in the breath and sweat of a person.

So the researchers collected breath and sweat samples (样品) from 36 different people. They got samples when the people were calm, and also when they were stressed. To stress people out, the scientists asked a really difficult math problem, and forced people to do it in their heads quickly. And they weren’t nice about it. They kept telling the people to hurry up, and didn’t give them any help. That lasted for three minutes. Then the researchers collected two more sweat and breath samples. They also asked the people about their level of stress, and measured their heart rates and blood pressure. Most people said they felt very stressed. On average, the heart rate increased from about 91 beats per minute to about 105 beats per minute.

The scientists used one of the stressed samples, along with two clean pieces of cloth, to train the dogs to find the stressed smell. Then came the challenge- the dogs had three choices: a sample from a calm person, a stressed sample from that same person, and a clean piece of cloth. In all, the dogs did 720 of these tests. They correctly identified the stressed sample about 94% of the time.