This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Example Input: Passage: Compact Disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982. Question: What does SVCD stand for?
Example Output: Super Video Compact Disc

Example Input: Passage: The Yuan dynasty is considered both a successor to the Mongol Empire and an imperial Chinese dynasty. It was the khanate ruled by the successors of Möngke Khan after the division of the Mongol Empire. In official Chinese histories, the Yuan dynasty bore the Mandate of Heaven, following the Song dynasty and preceding the Ming dynasty. The dynasty was established by Kublai Khan, yet he placed his grandfather Genghis Khan on the imperial records as the official founder of the dynasty as Taizu.[b] In the Proclamation of the Dynastic Name (《建國號詔》), Kublai announced the name of the new dynasty as Great Yuan and claimed the succession of former Chinese dynasties from the Three Sovereigns and Five Emperors to the Tang dynasty. Question: Who was Kublai Khan's grandfather?
Example Output: Genghis Khan

Example Input: Passage: Modern evolutionary theory continues to develop. Darwin's theory of evolution by natural selection, with its tree-like model of branching common descent, has become the unifying theory of the life sciences. The theory explains the diversity of living organisms and their adaptation to the environment. It makes sense of the geologic record, biogeography, parallels in embryonic development, biological homologies, vestigiality, cladistics, phylogenetics and other fields, with unrivalled explanatory power; it has also become essential to applied sciences such as medicine and agriculture. Despite the scientific consensus, a religion-based political controversy has developed over how evolution is taught in schools, especially in the United States. Question: What kind of controversy has begun within school systems about Darwin's theory?
Example Output:
a religion-based political controversy