This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: Multiracial Americans are Americans who have mixed ancestry of "two or more races". The term may also include Americans of mixed-race ancestry who self-identify with just one group culturally and socially (cf. the one-drop rule). In the 2010 US census, approximately 9 million individuals, or 2.9% of the population, self-identified as multiracial. There is evidence that an accounting by genetic ancestry would produce a higher number, but people live according to social and cultural identities, not DNA. Historical reasons, including slavery creating a racial caste and the European-American suppression of Native Americans, often led people to identify or be classified by only one ethnicity, generally that of the culture in which they were raised. Prior to the mid-20th century, many people hid their multiracial heritage because of racial discrimination against minorities. While many Americans may be biologically multiracial, they often do not know it or do not identify so culturally, any more than they maintain all the differing traditions of a variety of national ancestries. Question: Why did muticultural Americans hid their heritage?
many people hid their multiracial heritage because of racial discrimination against minorities

Passage: A HDI of 0.8 or more is considered to represent "high development". This includes all developed countries, such as those in North America, Western Europe, Oceania, and Eastern Asia, as well as some developing countries in Eastern Europe, Central and South America, Southeast Asia, the Caribbean, and the oil-rich Arabian Peninsula. Seven countries were promoted to this category this year, leaving the "medium development" group: Albania, Belarus, Brazil, Libya, Macedonia, Russia and Saudi Arabia. Question: What number indicates the minimum score for a country to be considered a "high development" country?
0.8

Passage: Stansted Airport, north east of London in Essex, is a local UK hub and Luton Airport to the north of London in Bedfordshire, caters mostly for cheap short-haul flights. London City Airport, the smallest and most central airport, in Newham, East London, is focused on business travellers, with a mixture of full service short-haul scheduled flights and considerable business jet traffic. London Southend Airport, east of London in Essex, is a smaller, regional airport that mainly caters for cheap short-haul flights. Question: What is the smallest airport in the London area?
London City Airport