Question: In 1972, in a mosque in the city of Sana'a, Yemen, manuscripts were discovered that were later proved to be the most ancient Quranic text known to exist at the time. The Sana'a manuscripts contain palimpsests, a manuscript page from which the text has been washed off to make the parchment reusable again—a practice which was common in ancient times due to scarcity of writing material. However, the faint washed-off underlying text (scriptio inferior) is still barely visible and believed to be "pre-Uthmanic" Quranic content, while the text written on top (scriptio superior) is believed to belong to Uthmanic time. Studies using radiocarbon dating indicate that the parchments are dated to the period before 671 AD with a 99 percent probability.
Is there an answer to this question: In which city was evidence of pre-Uthmanic Quranic writing discovered in 1972?

Answer: Sana'a, Yemen


Question: Instead, he formulated the spearhead model of evolution, a version of genetic pluralism. According to this model, living organisms themselves have goals, and act according to these goals, each guided by a central control. In its most sophisticated form, this is the brain of humans, but controls also exist in much less sophisticated ways for species of lower complexity, such as the amoeba. This control organ plays a special role in evolution—it is the "spearhead of evolution". The goals bring the purpose into the world. Mutations in the genes that determine the structure of the control may then cause drastic changes in behaviour, preferences and goals, without having an impact on the organism's phenotype. Popper postulates that such purely behavioural changes are less likely to be lethal for the organism compared to drastic changes of the phenotype.
Is there an answer to this question: What does Popper think is more likely to be lethal to an organism than changes of phenotype?

Answer: unanswerable


Question: Catalina Highway stretches 25 miles (40 km) and the entire mountain range is one of Tucson's most popular vacation spots for cycling, hiking, rock climbing, camping, birding, and wintertime snowboarding and skiing. Near the top of Mt. Lemmon is the town of Summerhaven. In Summerhaven, visitors will find log houses and cabins, a general store, and various shops, as well as numerous hiking trails. Near Summerhaven is the road to Ski Valley which hosts a ski lift, several runs, a giftshop, and nearby restaurant.
Is there an answer to this question: How many miles is Catalina Highway?

Answer: 25


Question: The theory of special relativity finds a convenient formulation in Minkowski spacetime, a mathematical structure that combines three dimensions of space with a single dimension of time. In this formalism, distances in space can be measured by how long light takes to travel that distance, e.g., a light-year is a measure of distance, and a meter is now defined in terms of how far light travels in a certain amount of time. Two events in Minkowski spacetime are separated by an invariant interval, which can be either space-like, light-like, or time-like. Events that have a time-like separation cannot be simultaneous in any frame of reference, there must be a temporal component (and possibly a spatial one) to their separation. Events that have a space-like separation will be simultaneous in some frame of reference, and there is no frame of reference in which they do not have a spatial separation. Different observers may calculate different distances and different time intervals between two events, but the invariant interval between the events is independent of the observer (and his velocity).
Is there an answer to this question: What are two events in Minkowski spacetime connected by?

Answer:
unanswerable