At high altitudes, Neptune's atmosphere is 80% hydrogen and 19% helium. A trace amount of methane is also present. Prominent absorption bands of methane exist at wavelengths above 600 nm, in the red and infrared portion of the spectrum. As with Uranus, this absorption of red light by the atmospheric methane is part of what gives Neptune its blue hue, although Neptune's vivid azure differs from Uranus's milder cyan. Because Neptune's atmospheric methane content is similar to that of Uranus, some unknown atmospheric constituent is thought to contribute to Neptune's colour.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What planet also gets it's color from atmospheric constituent? 
Ah, so.. Uranus

From about 1800 a fresh influx of Greek architectural examples, seen through the medium of etchings and engravings, gave a new impetus to neoclassicism, the Greek Revival. There was little to no direct knowledge of Greek civilization before the middle of the 18th century in Western Europe, when an expedition funded by the Society of Dilettanti in 1751 and led by James Stuart and Nicholas Revett began serious archaeological enquiry. Stuart was commissioned after his return from Greece by George Lyttelton to produce the first Greek building in England, the garden temple at Hagley Hall (1758–59). A number of British architects in the second half of the century took up the expressive challenge of the Doric from their aristocratic patrons, including Joseph Bonomi and John Soane, but it was to remain the private enthusiasm of connoisseurs up to the first decade of the 19th century.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Prior to what century had there been little contact between western europe and greek civilization?
Ah, so.. 18th century

Persistent infections occur because the body is unable to clear the organism after the initial infection. Persistent infections are characterized by the continual presence of the infectious organism, often as latent infection with occasional recurrent relapses of active infection. There are some viruses that can maintain a persistent infection by infecting different cells of the body. Some viruses once acquired never leave the body. A typical example is the herpes virus, which tends to hide in nerves and become reactivated when specific circumstances arise.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What never leave the body when acquired?
Ah, so..
Some viruses