How many countries share a land border with China? Answer with the whole number only.
In what year did Alaska Air Group complete its acquisition of Hawaiian Airlines? Answer with the four-digit year only.
What is the two-character IATA code of KLM? Answer with the two-character code only.
What is the IATA code of Paris Charles de Gaulle Airport? Answer with the three-letter code only.
In what year did Niels Bohr publish his model of the hydrogen atom? Answer with the four-digit year only.
In what year did Clyde Tombaugh discover Pluto? Answer with the four-digit year only.
In which country is the temple complex of Angkor Wat? Answer with the country name only.
What is the flag carrier airline of the Netherlands? Answer with the airline name only.
In what year did Theodore Maiman demonstrate the first working laser? Answer with the four-digit year only.
Which dwarf planet is the largest object in the asteroid belt? Answer with the name only.
How many time zones span the contiguous United States? Answer with the whole number only.
Which airline alliance does British Airways belong to? Answer with the alliance's full name.
In what year was the Hubble Space Telescope launched? Answer with the four-digit year only.
Who led the team that built Chicago Pile-1, the first nuclear reactor? Answer with the surname only.
What is the two-character IATA code of Qatar Airways? Answer with the two-character code only.
Which particle carries the electromagnetic force? Answer with the particle name only, in lowercase.
Mercury has at least one natural moon. Answer true or false.
In what year did Amelia Earhart disappear over the Pacific? Answer with the four-digit year only.
The Moon has a thick atmosphere. Answer true or false.
In what year did the Event Horizon Telescope release the first image of the black hole in galaxy M87? Answer with the four-digit year only.