This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Example Input: Theoretical analyses show that detours that increase flight distance by up to 20% will often be adaptive on aerodynamic grounds - a bird that loads itself with food to cross a long barrier flies less efficiently. However some species show circuitous migratory routes that reflect historical range expansions and are far from optimal in ecological terms. An example is the migration of continental populations of Swainson's thrush Catharus ustulatus, which fly far east across North America before turning south via Florida to reach northern South America; this route is believed to be the consequence of a range expansion that occurred about 10,000 years ago. Detours may also be caused by differential wind conditions, predation risk, or other factors.
Example Output: What percentage increase in flight distance will often be adaptive?

Example Input: In game play, players attempt to create goal-scoring opportunities through individual control of the ball, such as by dribbling, passing the ball to a team-mate, and by taking shots at the goal, which is guarded by the opposing goalkeeper. Opposing players may try to regain control of the ball by intercepting a pass or through tackling the opponent in possession of the ball; however, physical contact between opponents is restricted. Football is generally a free-flowing game, with play stopping only when the ball has left the field of play or when play is stopped by the referee for an infringement of the rules. After a stoppage, play recommences with a specified restart.
Example Output: Who guards the goal?

Example Input: Stemmatics, stemmology or stemmatology is a rigorous approach to textual criticism. Karl Lachmann (1793–1851) greatly contributed to making this method famous, even though he did not invent it. The method takes its name from the word stemma. The Ancient Greek word στέμματα and its loanword in classical Latin stemmata may refer to "family trees". This specific meaning shows the relationships of the surviving witnesses (the first known example of such a stemma, albeit with the name, dates from 1827). The family tree is also referred to as a cladogram. The method works from the principle that "community of error implies community of origin." That is, if two witnesses have a number of errors in common, it may be presumed that they were derived from a common intermediate source, called a hyparchetype. Relations between the lost intermediates are determined by the same process, placing all extant manuscripts in a family tree or stemma codicum descended from a single archetype. The process of constructing the stemma is called recension, or the Latin recensio.
Example Output:
What is stemmatics?