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

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.
optical effect

Which country is ranked at position 180 for the 2014 Press Freedom Index made by Reporters Without Borders?, Context: In its 2014 Press Freedom Index, Reporters Without Borders ranked the media environment in Eritrea at the very bottom of a list of 178 countries, just below totalitarian North Korea. According to the BBC, "Eritrea is the only African country to have no privately owned news media", and Reporters Without Borders said of the public media, "[they] do nothing but relay the regime's belligerent and ultra-nationalist discourse. ... Not a single [foreign correspondent] now lives in Asmara." The state-owned news agency censors news about external events. Independent media have been banned since 2001. In 2015, The Guardian published an opinion piece claiming,
Eritrea

What do the subjects do?, Context: When not celebrating Mass but still serving a liturgical function, such as the semiannual Urbi et Orbi papal blessing, some Papal Masses and some events at Ecumenical Councils, cardinal deacons can be recognized by the dalmatics they would don with the simple white mitre (so called mitra simplex).
they would don with the simple white mitre