21.  The boxfish is related to the better-known puffer fish and lives primarily in tropical waters around coral reefs in the Pacific Ocean.

22.  The eastern seaboard is no longer a paradise of palms, white beaches and clear tropical waters.

23.  The latest signs of El Nino, he said, were record high surface temperatures in tropical waters of the Pacific Ocean.

24.  The walrus-like mammals feed on vegetation in shallow tropical waters.