Which volcanic feature is formed by the collapse of a volcano's cone?

What strait separates the islands of Java and Madura in Indonesia? What strait separates the islands of Borneo and Sumatra in Indonesia? What is the term for a fast-moving current of hot ash, gas, and rock that flows down the side of a volcano? Which of the following volcanoes is known for its perfectly symmetrical cone shape? Which of the following volcanoes is located in the Andes mountain range? Which of the following volcanoes is located in the Pacific Ring of Fire? Which of the following volcanoes is located in the Hawaiian Islands? Which of the following volcanoes is located in the Cascade Range?