Question: Britain had successful tested a new HAA gun, 3.6-inch, in 1918. In 1928 3.7-inch became the preferred solution, but it took 6 years to gain funding. Production of the QF 3.7-inch (94 mm) began in 1937; this gun was used both on mobile carriages with the field army and transportable guns on fixed mountings for static positions. At the same time the Royal Navy adopted a new 4.5-inch (114 mm) gun in a twin turret, which the army adopted in simplified single-gun mountings for static positions, mostly around ports where naval ammunition was available. However, the performance of both 3.7 and 4.5-in guns was limited by their standard fuse No 199, with a 30-second running time, although a new mechanical time fuse giving 43 seconds was nearing readiness. In 1939 a Machine Fuse Setter was introduced to eliminate manual fuse setting.
Is there an answer to this question: What gun did the Royal Navy start using?

Answer: 4.5-inch (114 mm) gun in a twin turret

Question: Many birds show plumage patterns in ultraviolet that are invisible to the human eye; some birds whose sexes appear similar to the naked eye are distinguished by the presence of ultraviolet reflective patches on their feathers. Male blue tits have an ultraviolet reflective crown patch which is displayed in courtship by posturing and raising of their nape feathers. Ultraviolet light is also used in foragingkestrels have been shown to search for prey by detecting the UV reflective urine trail marks left on the ground by rodents. The eyelids of a bird are not used in blinking. Instead the eye is lubricated by the nictitating membrane, a third eyelid that moves horizontally. The nictitating membrane also covers the eye and acts as a contact lens in many aquatic birds. The bird retina has a fan shaped blood supply system called the pecten. Most birds cannot move their eyes, although there are exceptions, such as the great cormorant. Birds with eyes on the sides of their heads have a wide visual field, while birds with eyes on the front of their heads, such as owls, have binocular vision and can estimate the depth of field. The avian ear lacks external pinnae but is covered by feathers, although in some birds, such as the Asio, Bubo and Otus owls, these feathers form tufts which resemble ears. The inner ear has a cochlea, but it is not spiral as in mammals.
Is there an answer to this question: What covers the eye and acts as a contact lens in many aquatic birds?

Answer: nictitating membrane

Question: The Inequality-adjusted Human Development Index (IHDI) is a "measure of the average level of human development of people in a society once inequality is taken into account."
Is there an answer to this question: Does the IHDI measure the "abnormal" or the "lack of potential" level of human development?

Answer: unanswerable

Question: After the decline of Aksum, the Eritrean highlands were under the domain of Bahr Negash ruled by the Bahr Negus. The area was then known as Ma'ikele Bahr ("between the seas/rivers," i.e. the land between the Red Sea and the Mereb river). It was later renamed under Emperor Zara Yaqob as the domain of the Bahr Negash, the Medri Bahri ("Sea land" in Tingrinya, although it included some areas like Shire on the other side of the Mereb, today in Ethiopia). With its capital at Debarwa, the state's main provinces were Hamasien, Serae and Akele Guzai.
Is there an answer to this question: What was the capital of the Aksum?

Answer:
unanswerable