instruction:
In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
question:
How do chruches of christ worship in song?, Context: Present-day Christian religious bodies known for conducting their worship services without musical accompaniment include some Presbyterian churches devoted to the regulative principle of worship, Old Regular Baptists, Primitive Baptists, Plymouth Brethren, Churches of Christ, the Old German Baptist Brethren, Doukhobors the Byzantine Rite and the Amish, Old Order Mennonites and Conservative Mennonites. Certain high church services and other musical events in liturgical churches (such as the Roman Catholic Mass and the Lutheran Divine Service) may be a cappella, a practice remaining from apostolic times. Many Mennonites also conduct some or all of their services without instruments. Sacred Harp, a type of folk music, is an a cappella style of religious singing with shape notes, usually sung at singing conventions.
answer:
without musical accompaniment


question:
How large is the island of Guam?, Context: The island of Guam is 30 miles (50 km) long and 4 to 12 miles (6 to 19 km) wide, 3⁄4 the size of Singapore. The island experiences occasional earthquakes due to its location on the western edge of the Pacific Plate and near the Philippine Sea Plate. In recent years, earthquakes with epicenters near Guam have had magnitudes ranging from 5.0 to 8.7. Unlike the Anatahan volcano in the Northern Mariana Islands, Guam is not volcanically active. However, due to its proximity to Anatahan, vog (i.e. volcanic smog) does occasionally affect Guam.
answer:
3⁄4 the size of Singapore


question:
In what region do turbines run at 1500 RPM?, Context: A steam turbine consists of one or more rotors (rotating discs) mounted on a drive shaft, alternating with a series of stators (static discs) fixed to the turbine casing. The rotors have a propeller-like arrangement of blades at the outer edge. Steam acts upon these blades, producing rotary motion. The stator consists of a similar, but fixed, series of blades that serve to redirect the steam flow onto the next rotor stage. A steam turbine often exhausts into a surface condenser that provides a vacuum. The stages of a steam turbine are typically arranged to extract the maximum potential work from a specific velocity and pressure of steam, giving rise to a series of variably sized high- and low-pressure stages. Turbines are only efficient if they rotate at relatively high speed, therefore they are usually connected to reduction gearing to drive lower speed applications, such as a ship's propeller. In the vast majority of large electric generating stations, turbines are directly connected to generators with no reduction gearing. Typical speeds are 3600 revolutions per minute (RPM) in the USA with 60 Hertz power, 3000 RPM in Europe and other countries with 50 Hertz electric power systems. In nuclear power applications the turbines typically run at half these speeds, 1800 RPM and 1500 RPM. A turbine rotor is also only capable of providing power when rotating in one direction. Therefore, a reversing stage or gearbox is usually required where power is required in the opposite direction.[citation needed]
answer:

Europe