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 many birds migrate in flocks?, Context: Many, if not most, birds migrate in flocks. For larger birds, flying in flocks reduces the energy cost. Geese in a V-formation may conserve 12–20% of the energy they would need to fly alone. Red knots Calidris canutus and dunlins Calidris alpina were found in radar studies to fly 5 km/h (3.1 mph) faster in flocks than when they were flying alone.
answer:
most


question:
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.
answer:
optical effect


question:
What was the catalyst for the dissolution of the Vestals?, Context: Augustus' religious reformations raised the funding and public profile of the Vestals. They were given high-status seating at games and theatres. The emperor Claudius appointed them as priestesses to the cult of the deified Livia, wife of Augustus. They seem to have retained their religious and social distinctions well into the 4th century, after political power within the Empire had shifted to the Christians. When the Christian emperor Gratian refused the office of pontifex maximus, he took steps toward the dissolution of the order. His successor Theodosius I extinguished Vesta's sacred fire and vacated her temple.
answer:

When the Christian emperor Gratian refused the office of pontifex maximus