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.

Ex Input:
Passage: Photorespiration can occur when the oxygen concentration is too high. Rubisco cannot distinguish between oxygen and carbon dioxide very well, so it can accidentally add O2 instead of CO2 to RuBP. This process reduces the efficiency of photosynthesisit consumes ATP and oxygen, releases CO2, and produces no sugar. It can waste up to half the carbon fixed by the Calvin cycle. Several mechanisms have evolved in different lineages that raise the carbon dioxide concentration relative to oxygen within the chloroplast, increasing the efficiency of photosynthesis. These mechanisms are called carbon dioxide concentrating mechanisms, or CCMs. These include Crassulacean acid metabolism, C4 carbon fixation, and pyrenoids. Chloroplasts in C4 plants are notable as they exhibit a distinct chloroplast dimorphism. Question: When does photorespiration happen?

Ex Output:
when the oxygen concentration is too high

Ex Input:
Passage: A cover story in BusinessWeek magazine claims that economists mostly failed to predict the worst international economic crisis since the Great Depression of the 1930s. The Wharton School of the University of Pennsylvania's online business journal examines why economists failed to predict a major global financial crisis. Popular articles published in the mass media have led the general public to believe that the majority of economists have failed in their obligation to predict the financial crisis. For example, an article in the New York Times informs that economist Nouriel Roubini warned of such crisis as early as September 2006, and the article goes on to state that the profession of economics is bad at predicting recessions. According to The Guardian, Roubini was ridiculed for predicting a collapse of the housing market and worldwide recession, while The New York Times labelled him "Dr. Doom". Question: Which school at University of Pennsylvania examined in their online business journal why economists failed to predict the crisis?

Ex Output:
The Wharton School

Ex Input:
Passage: Greece is home to the first advanced civilizations in Europe and is considered the birthplace of Western civilization,[citation clutter] beginning with the Cycladic civilization on the islands of the Aegean Sea at around 3200 BC, the Minoan civilization in Crete (27001500 BC), and then the Mycenaean civilization on the mainland (19001100 BC). These civilizations possessed writing, the Minoans writing in an undeciphered script known as Linear A, and the Mycenaeans in Linear B, an early form of Greek. The Mycenaeans gradually absorbed the Minoans, but collapsed violently around 1200 BC, during a time of regional upheaval known as the Bronze Age collapse. This ushered in a period known as the Greek Dark Ages, from which written records are absent. Question: What is the time period called from which no writing can be found.

Ex Output:
Greek Dark Ages