Question: The deliberate or accidental hybridising of two or more species of closely related animals through captive breeding is a human activity which has been in existence for millennia and has grown in recent times for economic purposes. The number of successful interspecific mammalian hybrids is relatively small, although it has come to be known that there is a significant number of naturally occurring hybrids between forms or regional varieties of a single species.[citation needed] These may form zones of gradation known as clines. Indeed, the distinction between some hitherto distinct species can become clouded once it can be shown that they may not only breed but produce fertile offspring. Some hybrid animals exhibit greater strength and resilience than either parent. This is known as hybrid vigor. The existence of the mule (donkey sire; horse dam) being used widely as a hardy draught animal throughout ancient and modern history is testament to this. Other well known examples are the lion/tiger hybrid, the liger, which is by far the largest big cat and sometimes used in circuses; and cattle hybrids such as between European and Indian domestic cattle or between domestic cattle and American bison, which are used in the meat industry and marketed as Beefalo. There is some speculation that the donkey itself may be the result of an ancient hybridisation between two wild ass species or sub-species. Hybrid animals are normally infertile partly because their parents usually have slightly different numbers of chromosomes, resulting in unpaired chromosomes in their cells, which prevents division of sex cells and the gonads from operating correctly, particularly in males. There are exceptions to this rule, especially if the speciation process was relatively recent or incomplete as is the case with many cattle and dog species. Normally behavior traits, natural hostility, natural ranges and breeding cycle differences maintain the separateness of closely related species and prevent natural hybridisation. However, the widespread disturbances to natural animal behaviours and range caused by human activity, cities, dumping grounds with food, agriculture, fencing, roads and so on do force animals together which would not normally breed. Clear examples exist between the various sub-species of grey wolf, coyote and domestic dog in North America. As many birds and mammals imprint on their mother and immediate family from infancy, a practice used by animal hybridizers is to foster a planned parent in a hybridization program with the same species as the one with which they are planned to mate.
Is there an answer to this question: What is the name given when zones of gradation exits?

Answer: clines


Question: The original model Famicom featured two game controllers, both of which were hardwired to the back of the console. The second controller lacked the START and SELECT buttons, but featured a small microphone. Relatively few games made use of this feature. The earliest produced Famicom units initially had square A and B buttons. This was changed to the circular designs because of the square buttons being caught in the controller casing when pressed down and glitches within the hardware causing the system to freeze occasionally while playing a game.
Is there an answer to this question:  What shape were the D and E buttons on the earliest Famicom controllers?

Answer: unanswerable


Question: Later wax effigies include a likeness of Horatio, Viscount Nelson, wearing some of his own clothes and another of Prime Minister William Pitt, Earl of Chatham, modelled by the American-born sculptor Patience Wright.[citation needed] During recent conservation of Elizabeth I's effigy, a unique corset dating from 1603 was found on the figure and is now displayed separately.[citation needed]
Is there an answer to this question: What aren't the effigies made of?

Answer: unanswerable


Question: The city struck fortune in the late 18th century with the inventions and industrial activity of Eli Whitney, a Yale graduate who remained in New Haven to develop the cotton gin and establish a gun-manufacturing factory in the northern part of the city near the Hamden town line. That area is still known as Whitneyville, and the main road through both towns is known as Whitney Avenue. The factory is now the Eli Whitney Museum, which has a particular emphasis on activities for children and exhibits pertaining to the A. C. Gilbert Company. His factory, along with that of Simeon North, and the lively clock-making and brass hardware sectors, contributed to making early Connecticut a powerful manufacturing economy; so many arms manufacturers sprang up that the state became known as "The Arsenal of America". It was in Whitney's gun-manufacturing plant that Samuel Colt invented the automatic revolver in 1836. The Farmington Canal, created in the early 19th century, was a short-lived transporter of goods into the interior regions of Connecticut and Massachusetts, and ran from New Haven to Northampton, Massachusetts.
Is there an answer to this question: What was the nickname given to Connecticut due to the large number of arms manufacturers that arose in the state? 

Answer:
"The Arsenal of America"