In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

What is needed to prove the theory?, Context: In the early 11th century, the Muslim physicist Ibn al-Haytham (Alhacen or Alhazen) discussed space perception and its epistemological implications in his Book of Optics (1021), he also rejected Aristotle's definition of topos (Physics IV) by way of geometric demonstrations and defined place as a mathematical spatial extension. His experimental proof of the intromission model of vision led to changes in the understanding of the visual perception of space, contrary to the previous emission theory of vision supported by Euclid and Ptolemy. In "tying the visual perception of space to prior bodily experience, Alhacen unequivocally rejected the intuitiveness of spatial perception and, therefore, the autonomy of vision. Without tangible notions of distance and size for correlation, sight can tell us next to nothing about such things."
vision

What and how do some like to view things?, Context: Vowel length is not always considered a distinctive feature in Dutch phonology, because it normally co-occurs with changes in vowel quality. One feature or the other may be considered redundant, and some phonemic analyses prefer to treat it as an opposition of tenseness. However, even if not considered part of the phonemic opposition, the long/tense vowels are still realised as phonetically longer than their short counterparts. The changes in vowel quality are also not always the same in all dialects, and in some there may be little difference at all, with length remaining the primary distinguishing feature. And while it is true that older words always pair vowel length with a change in vowel quality, new loanwords have reintroduced phonemic oppositions of length. Compare zonne(n) [ˈzɔnə] ("suns") versus zone [ˈzɔːnə] ("zone") versus zonen [ˈzoːnə(n)] ("sons"), or kroes [krus] ("mug") versus cruise [kruːs] ("cruise").
One feature or the other may be considered redundant, and some phonemic analyses prefer to treat it as an opposition of tenseness

Despite what improvements were there still civil issues?, Context: Between 1346 and 1354, Tai Situ Changchub Gyaltsen toppled the Sakya and founded the Phagmodrupa Dynasty. The following 80 years saw the founding of the Gelug school (also known as Yellow Hats) by the disciples of Je Tsongkhapa, and the founding of the important Ganden, Drepung and Sera monasteries near Lhasa. However, internal strife within the dynasty and the strong localism of the various fiefs and political-religious factions led to a long series of internal conflicts. The minister family Rinpungpa, based in Tsang (West Central Tibet), dominated politics after 1435. In 1565 they were overthrown by the Tsangpa Dynasty of Shigatse which expanded its power in different directions of Tibet in the following decades and favoured the Karma Kagyu sect.
founding of the Gelug school (also known as Yellow Hats) by the disciples of Je Tsongkhapa, and the founding of the important Ganden, Drepung and Sera monasteries near Lhasa