How many planets in the Solar System have ring systems? Answer with the whole number only.
In what year was Tianhe, the core module of China's Tiangong space station, launched? Answer with the four-digit year only.
In what year did Henry Cavendish carry out his experiment to measure the density of the Earth? Answer with the four-digit year only.
What is the capital of Morocco? Answer with the city name only.
In what year did Hayabusa2 return its asteroid Ryugu samples to Earth? Answer with the four-digit year only.
What is the two-character IATA code of China Eastern Airlines? 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 the Airbus A380 enter commercial service? Answer with the four-digit year only.
In what year did Amelia Earhart disappear over the Pacific? Answer with the four-digit year only.
In what year was Ivy Mike, the first full-scale hydrogen bomb test, detonated? Answer with the four-digit year only.
In what year was Halley's Comet last at perihelion? Answer with the four-digit year only.
In what year did the Boeing 707 enter commercial service? Answer with the four-digit year only.
In what year did the Philae lander touch down on a comet? Answer with the four-digit year only.
What is the capital of Ethiopia? Answer with the city name only.
In what year did American Airlines and US Airways complete their merger? Answer with the four-digit year only.
In what year did Erwin Schrodinger publish his wave equation? Answer with the four-digit year only.
In what year did Werner Heisenberg publish the uncertainty principle? Answer with the four-digit year only.
