Q: Extract the answer to the question from the following context. Question: Which time period happened second, the early Ordovician or the end of the Carboniferous? Context: Since annelids are soft-bodied, their fossils are rare. Polychaetes' fossil record consists mainly of the jaws that some species had and the mineralized tubes that some secreted. Some Ediacaran fossils such as Dickinsonia in some ways resemble polychaetes, but the similarities are too vague for these fossils to be classified with confidence. The small shelly fossil Cloudina, from 549 to 542 million years ago, has been classified by some authors as an annelid, but by others as a cnidarian (i.e. in the phylum to which jellyfish and sea anemones belong). Until 2008 the earliest fossils widely accepted as annelids were the polychaetes Canadia and Burgessochaeta, both from Canada's Burgess Shale, formed about 505 million years ago in the early Cambrian. Myoscolex, found in Australia and a little older than the Burgess Shale, was possibly an annelid. However, it lacks some typical annelid features and has features which are not usually found in annelids and some of which are associated with other phyla. Then Simon Conway Morris and John Peel reported Phragmochaeta from Sirius Passet, about 518 million years old, and concluded that it was the oldest annelid known to date. There has been vigorous debate about whether the Burgess Shale fossil Wiwaxia was a mollusc or an annelid. Polychaetes diversified in the early Ordovician, about 488 to 474 million years ago. It is not until the early Ordovician that the first annelid jaws are found, thus the crown-group cannot have appeared before this date and probably appeared somewhat later. By the end of the Carboniferous, about 299 million years ago, fossils of most of the modern mobile polychaete groups had appeared. Many fossil tubes look like those made by modern sessile polychaetes  , but the first tubes clearly produced by polychaetes date from the Jurassic, less than 199 million years ago.
A: the end of the Carboniferous

Q: Extract the answer to the question from the following context. Question: Bush competed with someone from? Context: Bush focused his campaign on national security, presenting himself as a decisive leader and contrasted Kerry as a "flip-flopper." This strategy was designed to convey to American voters the idea that Bush could be trusted to be tough on terrorism while Kerry would be "uncertain in the face of danger." Bush (just as his father did with Dukakis in the 1988 election) also sought to portray Kerry as a "Massachusetts liberal" who was out of touch with mainstream Americans. One of Kerry's slogans was "Stronger at home, respected in the world." This advanced the suggestion that Kerry would pay more attention to domestic concerns; it also encapsulated Kerry's contention that Bush had alienated American allies by his foreign policy.
A: Massachusetts

Q: Extract the answer to the question from the following context. Question: What caused passage to not be permitted to the mentioned destination? Context: The Exeter to Plymouth railway of the LSWR needs to be reopened to connect Cornwall and Plymouth to the rest of the UK railway system on an all weather basis. There are proposals to reopen the line from Tavistock to Bere Alston for a through service to Plymouth. On the night of 4 February 2014, amid high winds and extremely rough seas, part of the sea wall at Dawlish was breached washing away around 40 metres (130 ft) of the wall and the ballast under the railway immediately behind. The line was closed. Network Rail began repair work  and the line reopened on 4 April 2014. In the wake of widespread disruption caused by damage to the mainline track at Dawlish by coastal storms in February 2014, Network Rail are considering reopening the Tavistock to Okehampton and Exeter section of the line as an alternative to the coastal route.
A: high winds and extremely rough seas

Q: Extract the answer to the question from the following context. Question: What can lead to mammalian color variation? Context: Mammalian hair, also known as pelage, can vary in color between populations, organisms within a population, and even on the individual organism. Light-dark color variation is common in the mammalian taxa. Sometimes, this color variation is determined by age variation, however, in other cases, it is determined by other factors. Selective pressures, such as ecological interactions with other populations or environmental conditions, often lead to the variation in mammalian coloration. These selective pressures favor certain colors in order to increase survival. Camouflage is thought to be a major selection pressure shaping coloration in mammals, although there is also evidence that sexual selection, communication, and physiological processes may influence the evolution of coloration as well. Camouflage is the most predominant mechanism for color variation, as it aids in the concealment of the organisms from predators or from their prey. Coat color can also be for intraspecies communication such as warning members of their species about predators, indicating health for reproductive purposes, communicating between mother and young, and intimidating predators. Studies have shown that in some cases, differences in female and male coat color could indicate information nutrition and hormone levels, which are important in the mate selection process. One final mechanism for coat color variation is physiological response purposes, such as temperature regulation in tropical or arctic environments. Although much has been observed about color variation, much of the genetic that link coat color to genes is still unknown. The genetic sites where pigmentation genes are found are known to affect phenotype by: 1) altering the spatial distribution of pigmentation of the hairs, and 2) altering the density and distribution of the hairs. Quantitative trait mapping is being used to better understand the distribution of loci responsible for pigmentation variation. However, although the genetic sites are known, there is still much to...
A:
Selective pressures, such as ecological interactions with other populations or environmental conditions, often lead to the variation in mammalian coloration