. >> brown: special correspondent john tulenko visits a high school classroom in new york, where turmoil in the middle east offers a "teaching moment" for a lesson about refugees. >> i think it's very important to expose them to what's happening in the rest of the world. they don't understand that it's important to care about people. it's even important to care about people that you don't know. >> ifill: we explore why children's food allergies are now more common and more severe. >> ifill: and we close with a musical memory of the "big man," e street band saxophonist clarence clemons. >> ifill: that's all ahead on tonight's newshour. major funding for the pbs newshour has been provided by: >> oil companies have changed my country. >> oil companies can make a difference. >> we have the chance to build the economy. >> create jobs, keep people healthy, and improve schools. >> and our communities. >> in angola chevron helps train engineers, teachers and farmers, launch child's programs. it's not just good business. >> i'm hopeful about my country's future. >> it's my country's future. >> an