The average annual rainfall ranges from very low in the northern and southern fringes of the desert to nearly non-existent over the central and the eastern part. The thin northern fringe of the desert receives more winter cloudiness and rainfall due to the arrival of low pressure systems over the Mediterranean Sea along the polar front, although very attenuated by the rain shadow effects of the mountains and the annual average rainfall ranges from 100 mm (3,93 in) to 250 mm (9,84 in). For example, Biskra, Algeria and Ouarzazate, Morocco are found in this zone. The southern fringe of the desert along the border with the Sahel receives summer cloudiness and rainfall due to the arrival of the Intertropical Convergence Zone from the south and the annual average rainfall ranges from 100 mm (3,93 in) to 250 mm (9,84 in). For example, Timbuktu, Mali and Agadez, Niger are found in this zone. The vast central hyper-arid core of the desert is virtually never affected by northerly or southerly atmospheric disturbances and permanently remains under the influence of the strongest anticyclonic weather regime and the annual average rainfall can drop to less than 1 mm (0.04 in). In fact, most of the Sahara receives less than 20 mm (0.79 in). Of the 9,000,000 km2 of desert land in the Sahara, an area of about 2,800,000 km2 (about 31% of the total area) receives an annual average rainfall amount of 10 mm (0.39 in) or less, while some 1,500,000 km2 (about 17% of the total area) receive an average of 5 mm or less. The annual average rainfall is virtually zero over a wide area of some 1,000,000 km2 in the eastern Sahara comprising deserts of Libya, Egypt and Sudan (Tazirbu, Kufra, Dakhla, Kharga, Farafra, Siwa, Asyut, Sohag, Luxor, Aswan, Abu Simbel, Wadi Halfa) where the long-term mean approximates 0.5 mm per year. The rainfall is very unreliable and erratic in the Sahara as it may vary considerably year by year. In full contrast to the negligible annual rainfall amounts, the annual rates of potential evaporation are extraordinarily high, roughly ranging from 2,500 mm/year to more than 6,000 mm/year in the whole desert. Nowhere else on Earth has air been found as dry and evaporative as in the Sahara region. With such an evaporative power, the Sahara can only be desiccated and dried out further more and the moisture deficit is tremendous.
What causes the southern fringe to receive cloudiness and   rainfall?
Intertropical Convergence Zone


Input: YouTube
In November 2008, 720p HD support was added. At the time of the 720p launch, the YouTube player was changed from a 4:3 aspect ratio to a widescreen 16:9. With this new feature, YouTube began a switchover to H.264/MPEG-4 AVC as its default video compression format. In November 2009, 1080p HD support was added. In July 2010, YouTube announced that it had launched a range of videos in 4K format, which allows a resolution of up to 4096×3072 pixels. In June 2015, support for 8K resolution was added, with the videos playing at 7680×4320 pixels.

When was 720p HD support added to youtube?
Output: In November 2008


Input: Article: Guinea-Bissau was once part of the kingdom of Gabu, as well as part of the Mali Empire. Parts of this kingdom persisted until the 18th century, while a few others were under some rule by the Portuguese Empire since the 16th century. In the 19th century, it was colonized as Portuguese Guinea. Upon independence, declared in 1973 and recognised in 1974, the name of its capital, Bissau, was added to the country's name to prevent confusion with Guinea (formerly French Guinea). Guinea-Bissau has a history of political instability since independence, and no elected president has successfully served a full five-year term.

Now answer this question: What empire was Guinea-Bissau once part of?

Output: Mali Empire


Article: The transition from the mandolino to the mandolin began around 1744 with the designing of the metal-string mandolin by the Vinaccia family, 3 brass strings and one of gut, using friction tuning pegs on a fingerboard that sat "flush" with the sound table. The mandolin grew in popularity over the next 60 years, in the streets where it was used by young men courting and by street musicians, and in the concert hall. After the Napoleonic Wars of 1815, however, its popularity began to fall. The 19th century produced some prominent players, including Bartolomeo Bortolazzi of Venice and Pietro Vimercati. However, professional virtuosity was in decline, and the mandolin music changed as the mandolin became a folk instrument; "the large repertoire of notated instrumental music for the mandolino and the mandoline was completely forgotten". The export market for mandolins from Italy dried up around 1815, and when Carmine de Laurentiis wrote a mandolin method in 1874, the Music World magazine wrote that the mandolin was "out of date." Salvador Léonardi mentioned this decline in his 1921 book, Méthode pour Banjoline ou Mandoline-Banjo, saying that the mandolin had been declining in popularity from previous times.

Question: Who were two of the promiment players in the 19th century?
Ans: Bartolomeo Bortolazzi of Venice and Pietro Vimercati


Here is a question about this article: Victoria wrote to her uncle Leopold, whom Victoria considered her "best and kindest adviser", to thank him "for the prospect of great happiness you have contributed to give me, in the person of dear Albert ... He possesses every quality that could be desired to render me perfectly happy. He is so sensible, so kind, and so good, and so amiable too. He has besides the most pleasing and delightful exterior and appearance you can possibly see." However at 17, Victoria, though interested in Albert, was not yet ready to marry. The parties did not undertake a formal engagement, but assumed that the match would take place in due time.
What is the answer to this question: Who was Victoria not ready to marry at age 17?
****
So... Albert


Article: No single feature distinguishes Annelids from other invertebrate phyla, but they have a distinctive combination of features. Their bodies are long, with segments that are divided externally by shallow ring-like constrictions called annuli and internally by septa ("partitions") at the same points, although in some species the septa are incomplete and in a few cases missing. Most of the segments contain the same sets of organs, although sharing a common gut, circulatory system and nervous system makes them inter-dependent. Their bodies are covered by a cuticle (outer covering) that does not contain cells but is secreted by cells in the skin underneath, is made of tough but flexible collagen and does not molt – on the other hand arthropods' cuticles are made of the more rigid α-chitin, and molt until the arthropods reach their full size. Most annelids have closed circulatory systems, where the blood makes its entire circuit via blood vessels.

Question: What covers an annelid's exterior?
Ans:
a cuticle