Given the task definition, example input & output, solve the new input case.
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
Example: Passage: Nearing London, Oliver encounters Jack Dawkins, a pickpocket more commonly known by the nickname the "Artful Dodger", and his sidekick, a boy of a humorous nature named Charley Bates, but Oliver's innocent and trusting nature fails to see any dishonesty in their actions. The Dodger provides Oliver with a free meal and tells him of a gentleman in London who will "give him lodgings for nothing, and never ask for change". Grateful for the unexpected assistance, Oliver follows the Dodger to the "old gentleman's" residence. In this way Oliver unwittingly falls in with an infamous Jewish criminal known as Fagin, the gentleman of whom the Artful Dodger spoke. Ensnared, Oliver lives with Fagin and his gang of juvenile pickpockets in their lair at Saffron Hill for some time, unaware of their criminal occupations. He believes they make wallets and handkerchiefs.
Output: Who believes Fagin's gang make wallets and handkerchiefs?.
This question is based on the following sentence in the passage "He believes they make wallets and handkerchiefs". It evaluates the understanding that the pronoun "he" refers to name "Oliver". You can ask questions like this one about most pronouns in a paragraph.

New input case for you: Passage: Big Butte Creek drains approximately 245 square miles (635 km2) of southern Oregon. Elevations range from 1,562 feet (476.1 m) at the creek's mouth to 9,495 feet (2,894 m) at the summit of Mount McLoughlin, with an average of 3,528 feet (1,075 m). About 56 percent is federally owned by the Bureau of Land Management and the United States Forest Service, 44 percent is privately owned, and a small fraction belongs to the City of Medford.The Big Butte Creek watershed experiences a Mediterranean climate. Temperatures range from 10 °F (−12 °C) in the winter to 100 °F (38 °C) in the summer. Precipitation averages between 35 and 80 inches (890 and 2,000 mm) annually. Most precipitation occurs between November and March. Nine percent of the watershed's surface runoff is collected from rain, 35 percent from rain on snow, and 56 percent from snow. The watershed contains the largest groundwater source in the entire Rogue River basin; one major outlet is at Big Butte Springs.The watershed is split into two geographic regions: the High Cascades and the Western Cascades, both volcanic in origin. The Western Cascades compose the western two thirds of the watershed. This region is highly eroded, being between 17 and 38 million years old. Its unstable slopes are primarily made of pyroclastic rock. Due to the rock's high ability to absorb moisture, earthflows are common. The High Cascades are much younger, around three to seven million years old. Mount McLoughlin is the most prominent High Cascade volcano in the watershed, last erupting between 20,000 and 15,000 years ago. Basalt and andesite are the most common rock types in this region.Nearby watersheds include Little Butte Creek to the south, small Klamath River tributaries such as Fourmile Creek to the east, the South Fork Rogue River to the east and north, and minor tributaries of the Rogue River including Reese and Indian creeks to the west.
Output:
What watershed is split into two geographic regions?