QUES: The exodus of Salvadorans was a result of both economic and political problems. The largest immigration wave occurred as a result of the Salvadoran Civil War in the 1980s, in which 20–30% of El Salvador's population emigrated. About 50%, or up to 500,000 of those who escaped headed to the United States, which was already home to over 10,000 Salvadorans, making Salvadorans Americans the fourth-largest Hispanic and Latino American group, after the Mexican-American majority, stateside Puerto Ricans, and Cubans.

How many Salvadorans immigrated?
What is the answer?
ANS: 20–30% of El Salvador's population emigrated. About 50%, or up to 500,000 of those who escaped headed to the United States,
QUES: In general relativity, a vanishing stress-energy tensor implies, through Einstein field equations, the vanishing of all the components of the Ricci tensor. Vacuum does not mean that the curvature of space-time is necessarily flat: the gravitational field can still produce curvature in a vacuum in the form of tidal forces and gravitational waves (technically, these phenomena are the components of the Weyl tensor). The black hole (with zero electric charge) is an elegant example of a region completely "filled" with vacuum, but still showing a strong curvature.

Tidal forces and gravitational waves can produce zero what?
What is the answer?
ANS: unanswerable
QUES: Sentient beings always suffer throughout saṃsāra until they free themselves from this suffering (dukkha) by attaining Nirvana. Then the absence of the first Nidāna—ignorance—leads to the absence of the others.

The absence of ignorance leads to what?
What is the answer?
ANS:
the absence of the others