In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

How can you reduce the jnd?, Context: The just-noticeable difference (jnd) (the threshold at which a change is perceived) depends on the tone's frequency content. Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents). The jnd is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches. The jnd becomes smaller if the two tones are played simultaneously as the listener is then able to discern beat frequencies. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.
two tones are played simultaneously

What is Compass-M1 like, Context: Compass-M1 is an experimental satellite launched for signal testing and validation and for the frequency filing on 14 April 2007. The role of Compass-M1 for Compass is similar to the role of the GIOVE satellites for the Galileo system. The orbit of Compass-M1 is nearly circular, has an altitude of 21,150 km and an inclination of 55.5 degrees.
GIOVE

How did Alexander III's father meet his fate?, Context: Following the assassination of Phillip II, his son Alexander III ("The Great") assumed the leadership of the League of Corinth and launched an invasion of the Persian Empire with the combined forces of all Greek states in 334 BC. Undefeated in battle, Alexander had conquered the Persian Empire in its entirety by 330 BC. By the time of his death in 323 BC, he had created one of the largest empires in history, stretching from Greece to India. His empire split into several kingdoms upon his death, the most famous of which were the Seleucid Empire, Ptolemaic Egypt, the Greco-Bactrian Kingdom and the Indo-Greek Kingdom. Many Greeks migrated to Alexandria, Antioch, Seleucia and the many other new Hellenistic cities in Asia and Africa. Although the political unity of Alexander's empire could not be maintained, it resulted in the Hellenistic civilization and spread the Greek language and Greek culture in the territories conquered by Alexander. Greek science, technology and mathematics are generally considered to have reached their peak during the Hellenistic period.
assassination