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.

Input: Consider Input: Passage: The Chief Deputy Whip is the primary assistant to the whip, who is the chief vote counter for his or her party. The current chief deputy majority whip is Republican Patrick McHenry. Within the House Republican Conference, the chief deputy whip is the highest appointed position and often a launching pad for future positions in the House Leadership. The House Democratic Conference has multiple chief deputy whips, led by a Senior Chief Deputy Whip, which is the highest appointed position within the House Democratic Caucus. The current senior chief deputy minority whip, John Lewis, has held his post since 1991. Question: How long has democratic leader of whips held position?

Output: senior chief deputy minority whip, John Lewis, has held his post since 1991


Input: Consider Input: Passage: Several references in Indian literature praise the knowledge of the Yavanas or the Greeks. The Mahabharata compliments them as "the all-knowing Yavanas" (sarvajnaa yavanaa) i.e. "The Yavanas, O king, are all-knowing; the Suras are particularly so. The mlecchas are wedded to the creations of their own fancy." and the creators of flying machines that are generally called vimanas. The "Brihat-Samhita" of the mathematician Varahamihira says: "The Greeks, though impure, must be honored since they were trained in sciences and therein, excelled others....." . Question: Who said "The Yavanas, O king, are all-knowing; the Suras are particularly so."?

Output: The Mahabharata


Input: Consider Input: Passage: The number of species invasions has been on the rise at least since the beginning of the 1900s. Species are increasingly being moved by humans (on purpose and accidentally). In some cases the invaders are causing drastic changes and damage to their new habitats (e.g.: zebra mussels and the emerald ash borer in the Great Lakes region and the lion fish along the North American Atlantic coast). Some evidence suggests that invasive species are competitive in their new habitats because they are subject to less pathogen disturbance. Others report confounding evidence that occasionally suggest that species-rich communities harbor many native and exotic species simultaneously while some say that diverse ecosystems are more resilient and resist invasive plants and animals. An important question is, "do invasive species cause extinctions?" Many studies cite effects of invasive species on natives, but not extinctions. Invasive species seem to increase local (i.e.: alpha diversity) diversity, which decreases turnover of diversity (i.e.: beta diversity). Overall gamma diversity may be lowered because species are going extinct because of other causes, but even some of the most insidious invaders (e.g.: Dutch elm disease, emerald ash borer, chestnut blight in North America) have not caused their host species to become extinct. Extirpation, population decline, and homogenization of regional biodiversity are much more common. Human activities have frequently been the cause of invasive species circumventing their barriers, by introducing them for food and other purposes. Human activities therefore allow species to migrate to new areas (and thus become invasive) occurred on time scales much shorter than historically have been required for a species to extend its range. Question: What invaders are causing changes in the Great Lakes region?


Output: zebra mussels and the emerald ash borer