In this task you will be given an answer to a question. You need to generate a question. The answer given should be a correct answer for the generated question.

[Q]: A callus is an area of thickened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on feet because of frequent walking and incorrectly fitting footwear. While they can be perceived as being unsightly, calluses are generally not harmful, but if neglected for long periods may sometimes lead to other problems, such as a skin ulceration or infection, or cause the sufferer to try and offload the affected painful area, which can place excessive stress on the asymptomatic side. Rubbing that is too frequent or forceful will cause blisters as opposed to calluses to form.
[A]: why do i have callus on my hands


[Q]: The world's first movable type printing press technology for printing paper books was made of porcelain materials and was invented around AD 1040 in China during the Northern Song Dynasty by the inventor Bi Sheng (990 -- 1051). Subsequently in 1377, the world's oldest extant movable metal print book, Jikji, was printed in Korea during the Goryeo dynasty. Because of this, the diffusion of both movable-type systems was, to some degree, limited to primarily East Asia, although various sporadic reports of movable type technology were brought back to Europe by Christian missionaries, traders and business people who were returning to Europe after having worked in China for several years and influenced the development of printing technology in Europe. Some of these medieval European accounts are still preserved in the library archives of the Vatican and Oxford University among many others. Around 1450 Johannes Gutenberg, introduced the metal movable-type printing press in Europe, along with innovations in casting the type based on a matrix and hand mould. The small number of alphabetic characters needed for European languages was an important factor. Gutenberg was the first to create his type pieces from an alloy of lead, tin, and antimony -- and these materials remained standard for 550 years.
[A]: who is given credit for inventing the printing press


[Q]: Grey matter in the spinal cord is known as the grey column which travels down the spinal cord distributed in three grey columns that are presented in an 'H' shape. The forward-facing column is the anterior grey column, the rear-facing one is the posterior grey column and the interlinking one is the lateral grey column. The grey matter on the left and right side is connected by the grey commissure. The grey matter in the spinal cord consists of interneurons, as well as the cell bodies of projection neurons.
[A]:
where is the grey matter of the spinal cord located