Welcome to American Mosaic from VOA Learning English. I'm June Simms.

　　Today on the show, we tell about some unusual young people who work to make a difference in the world.

　　Most teenagers in the United States spend their time trying to make time for school, family and friends. But some choose bigger goals. Christopher Cruise tells us about three American teens working to make a difference in the world.

　　At age 15, Winter Vinecki has already had more successes than most people have in their lifetime.

　　"I recently completed a marathon on all seven continents and became the youngest person in the world to do so. And, I was really doing this for my dad."

　　Doctors discovered Winter's father had a rare and aggressive form of prostate cancer when she was nine years old. He died 10 months later.

　　"When he was first diagnosed I immediately knew I had to do something to help him. That's when I formed Team Winter for prostate cancer research and awareness."

　　Through Team Winter and social media, Winter Vinecki has raised almost 500,000 dollars. She has taken prostate cancer education worldwide from Kenya to Mongolia through foot races called marathons, on seven continents. In the United States she travels continually to talk about prostate cancer and urge others to act.

　　Winter Vinecki spoke recently at a conference in Los Angeles, California. She was one of several teenagers who spoke about young people who are living extraordinary lives.

　　"So prostate cancer is much more common but the men don't want to talk about it. So that's why a nine-year-old girl had to go out there and start talking about it for them."

　　Another speaker was Jack Andraka. He invented an inexpensive sensor that identifies cancers of the pancreas, ovaries and lungs. He was 15 at the time.

　　"Without Google, Wikipedia, I would have never been able to learn all this stuff I needed for this project. I mean I didn't even know what a pancreas was before developing my test for pancreatic cancer."

　　Jack is now 17 and seeking patents for his latest inventions. He has developed low-cost water quality devices. They help identify and remove heavy metals and poisonous chemicals from water.

　　"I hope to see them employed in the developing nations such as Bangladesh and parts of China and India, especially as well as in parts of Africa, where these heavy metal and pesticides and other industrial effluents are a major problem."

　　Sixteen-year-old Mary-Pat Hector saw a problem in her own community. She says too many young people were dying in gun violence.

　　“It was seeing my friends hurt; it was seeing it on the television constantly. It kind of made me feel like I had to do something about it,” said Hector.

　　So Mary-Pat became the national youth director of one of the largest U.S. civil rights organizations, the National Action Network. She also started a campaign to educate young people about gun violence.

　　“My 8-year-old brother drives me, I think, about how innocent he is. I just want the world to be a better place for him and my children,” she said.

　　Mary-Pat Hector, Jack Andraka, and Winter Vinecki say a combination of supportive parents, the Internet and social media has helped them succeed; but Winter and Jack also created their inner selves.

　　“I think the biggest thing for kids and adults is to never let age and gender be a barrier and to not just dream but dream big,” said Vinecki.

　　“Never let anyone else tell you no," said Andraka. "Always keep going for your dream, and think if a 15-year-old could do it, just think what you could do.”

　　They say with that kind of thinking, anything is possible.

　　I'm June Simms. Join us again next week for American Mosaic from VOA Learning English.