On-air challenge: For each given category, name something in the category where the first letter is also the first letter of the category. For example, given "Military Ranks," you would say "Major."

Last week's challenge: Name a geographical location in two words — nine letters altogether — that, when spoken aloud, sounds roughly like four letters of the alphabet. What is it?

Answer: Aegean Sea; Indian Cay

Winner: Terry Thacker, Greenville, S.C.

Sokeel Park sees the effects of North Korea's repressive government every day. He lives in South Korea, but works for an NGO named Liberty in North Korea. His job is to debrief those who've managed to leave the North and help them start new lives in the South.

Park says that with so much focus on the country's nuclear weapons and leadership, it's easy to forget about the 24 million people going about their everyday lives. Those lives are heavily controlled by the North Korean government, citizens are told where to work, where to live, and are not allowed to leave.

In his systematic scrutiny of the modern American food chain, Michael Pollan has explored everything from the evolution of edible plants to the industrial agricultural complex. In his newest book, he charts territory closer to home — or rather, at home, in his kitchen.

Cooked: A Natural History of Transformation surveys how the four classical elements — fire, water, air and earth — transform plants and animals into food. Pollan joins NPR's Rachel Martin to discuss the merits of slow home cooking and his adventures in fermentation.

On Tuesday, Oklahoma and Texas will face off in the U.S. Supreme Court. The winner gets water. And this is not a game.

The court will hear oral arguments in the case of Tarrant Regional Water District v. Herrmann, et al. The case pits Oklahoma against Texas over rights to water from the river that forms part of the border between them. Depending on how the court decides, it could impact interstate water-sharing agreements across the country.

Keeping Up With Texas