Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Q: Context: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. Despite significant progresses in the last decades, the origin of this cancer remains unclear and no efficient therapy exists. PDAC does not arise de novo: three remarkable different types of pancreatic lesions can evolve towards pancreatic cancer. These precursor lesions include: Pancreatic intraepithelial neoplasia (PanIN) that are microscopic lesions of the pancreas, Intraductal Papillary Mucinous Neoplasms (IPMN) and Mucinous Cystic Neoplasms (MCN) that are both macroscopic lesions. However, the cellular origin of these lesions is still a matter of debate. Classically, neoplasm initiation or progression is driven by several genetic and epigenetic alterations. The aim of this review is to assemble the current information on genetic mutations and epigenetic disorders that affect genes during pancreatic carcinogenesis. We will further discuss the interest of the genetic and epigenetic alterations for the diagnosis and prognosis of PDAC. Large genetic alterations (chromosomal deletion/amplification) and single point mutations are well described for carcinogenesis inducers. Mutations classically occur within key regions of the genome. Consequences are various and include activation of mitogenic pathways or silencing of apoptotic processes. Alterations of K-RAS, P16 and DPC4 genes are frequently observed in PDAC samples and have been described to arise gradually during carcinogenesis. DNA methylation is an epigenetic process involved in imprinting and X chromosome inactivation. Alteration of DNA methylation patterns leads to deregulation of gene expression, in the absence of mutation. Both genetic and epigenetic events influence genes and non-coding RNA expression, with dramatic effects on proliferation, survival and invasion. Besides improvement in our fundamental understanding of PDAC development, highlighting the molecular alterations that occur in pancreatic carcinogenesis could provide new clinical tools for early diagnosis of PDAC and the molecular basis for the development of new effective therapies.
Question: Which is the molecular mechanism underlying K-ras alterations in carcinomas?

A: point mutations
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Q: Context: Hoping to rebound from a tough loss to the Patriots, the Bills would play their Week 2 home opener in an interconference duel with the Tampa Bay Buccaneers. This would be the first time that Buffalo ever hosted Tampa Bay in a regular season game, having played a preseason game with each other in 1977. In the first quarter, the Bills came out firing as quarterback Trent Edwards completed a 32-yard touchdown pass to wide receiver Lee Evans, safety Donte Whitner returning an interception 76 yards for a touchdown and kicker Rian Lindell making a 31-yard field goal. The Buccaneers would get on the board in the second quarter as quarterback Byron Leftwich completed a 42-yard touchdown pass to tight end Kellen Winslow, while Buffalo replied with Lindell getting a 43-yard field goal. Tampa Bay would close out the half as Leftwich completed an 8-yard touchdown pass to running back Carnell "Cadillac" Williams. After a scoreless third quarter, the Bills began to pull away as Lindell got a 43-yard field goal and Edwards completed a 43-yard touchdown pass to wide receiver Terrell Owens. The Buccaneers tried to rally as Leftwich completed a 6-yard touchdown pass to tight end Jerramy Stevens (with a failed two-point conversion), yet Buffalo closed out the game with Lindell nailing a 20-yard field goal. With the win, the Bills improved to 1-1.
Question: Who threw the fifth longest touchdown pass?

A: leftwich
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Q: Context: With more greenhouse gases trapping heat, average annual global temperatures are rising. This is known as global warming. While temperatures have risen since the end of the Pleistocene, 10,000 years ago, this rate of increase has been more rapid in the past century, and has risen even faster since 1990. The 10 warmest years in the 134-year record have all occurred since in the 21st century, and only one year during the 20th century (1998) was warmer than 2013, the 4th warmest year on record (through 2013) (Figure 1.1). The 2000s were the warmest decade yet. Annual variations aside, the average global temperature increased about 0.8o C (1.5o F) between 1880 and 2010, according to the Goddard Institute for Space Studies, NOAA. This number doesnt seem very large. Why is it important? The United States has long been the largest emitter of greenhouse gases, with about 20% of total emissions in 2004. As a result of Chinas rapid economic growth, its emissions surpassed those of the United States in 2008. However, its also important to keep in mind that the United States has only about one-fifth the population of China. Whats the significance of this? The average United States citizen produces far more greenhouse gas emissions than the average Chinese person. The following images show changes in the Earth and organisms as a result of global warming: Figure 1.2, Figure (a) Breakup of the Larsen Ice Shelf in Antarctica in 2002 was related to climate warming in the region. (b) The Boulder Glacier has melted back tremendously since 1985. Other mountain glaciers around the world are also melting. The timing of events for species is changing. Mating and migrations take place earlier in the spring months. Species that can are moving their ranges uphill. Some regions that were already marginal for agriculture are no longer arable because they have become too warm or dry. What are the two major effects being seen in this animation? Glaciers are melting and vegetation zones are moving uphill. If fossil fuel use exploded in the 1950s, why do these changes begin early in the animation? Does this mean that the climate change we are seeing is caused by natural processes and not by fossil fuel use? Permafrost is melting and its extent de- creasing. There are now fewer summer lakes in Siberia. (a) Melting ice caps add water to the oceans, so sea level is rising. Remember that water slightly expands as it warms this expansion is also causing sea level to rise. (b) Weather is becoming more variable with more severe storms and droughts. Snow blanketed the west- ern United States in December 2009. (c) As surface seas warm, phytoplankton productivity has decreased. (d) Coral reefs are dying worldwide; corals that are stressed by high temperatures turn white. (e) Pine beetle infestations have killed trees in western North America The insects have expanded their ranges into areas that were once too cold. Warming temperatures are bringing changes to much of the planet, including California. Sea level is rising, snow pack is changing, and the ecology of the state is responding to these changes. Click image to the left or use the URL below. URL:
Question: warmer temperatures are causing coral reefs to

A:
turn white.
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