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

Example Input: 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.
Example Output: optical effect

Example Input: How was Lithuania effected by the Crusades?, Context: With the onset of the Crusades in 1095, and the expulsions from England (1290), France (1394), and parts of Germany (15th century), Jewish migration pushed eastward into Poland (10th century), Lithuania (10th century), and Russia (12th century). Over this period of several hundred years, some have suggested, Jewish economic activity was focused on trade, business management, and financial services, due to several presumed factors: Christian European prohibitions restricting certain activities by Jews, preventing certain financial activities (such as "usurious" loans) between Christians, high rates of literacy, near universal male education, and ability of merchants to rely upon and trust family members living in different regions and countries.
Example Output: Jewish migration

Example Input: What keeps people from getting sick?, Context: In more recent applications, hydrogen is used pure or mixed with nitrogen (sometimes called forming gas) as a tracer gas for minute leak detection. Applications can be found in the automotive, chemical, power generation, aerospace, and telecommunications industries. Hydrogen is an authorized food additive (E 949) that allows food package leak testing among other anti-oxidizing properties.
Example Output:
E 949