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

[EX Q]: What is Rayleigh scattering?, Context: In nature, the red color of blood comes from hemoglobin, the iron-containing protein found in the red blood cells of all vertebrates. The red color of the Grand Canyon and other geological features is caused by hematite or red ochre, both forms of iron oxide. It also causes the red color of the planet Mars. The red sky at sunset and sunrise is caused by an optical effect known as Rayleigh scattering, which, when the sun is low or below the horizon, increases the red-wavelength light that reaches the eye. The color of autumn leaves is caused by pigments called anthocyanins, which are produced towards the end of summer, when the green chlorophyll is no longer produced. One to two percent of the human population has red hair; the color is produced by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin.
[EX A]: optical effect

[EX Q]: What was Charles V nationality?, Context: Martin Luther (/ˈluːθər/ or /ˈluːðər/; German: [ˈmaɐ̯tiːn ˈlʊtɐ] ( listen); 10 November 1483 – 18 February 1546) was a German professor of theology, composer, priest, former monk and a seminal figure in the Protestant Reformation. Luther came to reject several teachings and practices of the Late Medieval Catholic Church. He strongly disputed the claim that freedom from God's punishment for sin could be purchased with money. He proposed an academic discussion of the power and usefulness of indulgences in his Ninety-Five Theses of 1517. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the Pope and condemnation as an outlaw by the Emperor.
[EX A]: Roman

[EX Q]: What book describes the noble truths, Context: A core problem in the study of early Buddhism is the relation between dhyana and insight. Schmithausen, in his often-cited article On some Aspects of Descriptions or Theories of 'Liberating Insight' and 'Enlightenment' in Early Buddhism notes that the mention of the four noble truths as constituting "liberating insight", which is attained after mastering the Rupa Jhanas, is a later addition to texts such as Majjhima Nikaya 36.[page needed]
[EX A]:
Majjhima Nikaya