Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

[Q]: Passage: The first recorded settlement in what is now Newcastle was Pons Aelius, a Roman fort and bridge across the River Tyne. It was given the family name of the Roman Emperor Hadrian, who founded it in the 2nd century AD. This rare honour suggests that Hadrian may have visited the site and instituted the bridge on his tour of Britain. The population of Pons Aelius at this period was estimated at 2,000. Fragments of Hadrian's Wall are still visible in parts of Newcastle, particularly along the West Road. The course of the 'Roman Wall' can be traced eastwards to the Segedunum Roman fort in Wallsend—the 'wall's end'—and to the supply fort Arbeia in South Shields. The extent of Hadrian's Wall was 73 miles (117 km), spanning the width of Britain; the Wall incorporated the Vallum, a large rearward ditch with parallel mounds, and was constructed primarily for defence, to prevent unwanted immigration and the incursion of Pictish tribes from the north, not as a fighting line for a major invasion. Question: What tribes were the Romans fearful would invade from the North?
[A]: Pictish


[Q]: Passage: Despite their soft, gelatinous bodies, fossils thought to represent ctenophores, apparently with no tentacles but many more comb-rows than modern forms, have been found in lagerstätten as far back as the early Cambrian, about 515 million years ago. The position of the ctenophores in the evolutionary family tree of animals has long been debated, and the majority view at present, based on molecular phylogenetics, is that cnidarians and bilaterians are more closely related to each other than either is to ctenophores. A recent molecular phylogenetics analysis concluded that the common ancestor of all modern ctenophores was cydippid-like, and that all the modern groups appeared relatively recently, probably after the Cretaceous–Paleogene extinction event 66 million years ago. Evidence accumulating since the 1980s indicates that the 'cydippids' are not monophyletic, in other words do not include all and only the descendants of a single common ancestor, because all the other traditional ctenophore groups are descendants of various cydippids. Question: Fossils found that were believed to be ctenophores were how old?
[A]: 515 million years


[Q]: Passage: BSkyB's standard definition broadcasts are in DVB-compliant MPEG-2, with the Sky Movies and Sky Box Office channels including optional Dolby Digital soundtracks for recent films, although these are only accessible with a Sky+ box. Sky+ HD material is broadcast using MPEG-4 and most of the HD material uses the DVB-S2 standard. Interactive services and 7-day EPG use the proprietary OpenTV system, with set-top boxes including modems for a return path. Sky News, amongst other channels, provides a pseudo-video on demand interactive service by broadcasting looping video streams. Question: What is Sky+ HD material broadcast using?
[A]:
MPEG-4