Given the Question and Answer pair, detect whether the answer is acceptable or not. Denote acceptable answer as "yes", otherwise denote as "no". An acceptable answer is consistent with the context in question, detailed, long, and uses general knowledge of English. Answers that are not definite and suggest a variety of options are not acceptable answers.
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Question: Question: I am looking for a word or phrase which can be used in the sentence: It is a rather old, but _________________ technology. The word or phrase should address a technology that is totally investigated, researched in detail, and thoroughly optimised, so there is nothing more to find out or improve. 
Answer: I don't know of a technology that cannot be improved, but we often use the term mature to describe technology that's deemed developed enough to be left alone: A mature technology is a technology that has been in use for long enough that most of its initial faults and inherent problems have been removed or reduced by further development. In some contexts, it may also refer to technology that has not seen widespread use, but whose scientific background is well understood. Wikipedia mature 6. No longer subject to great expansion or development. Used of an industry, market, or product. American Heritage® Dictionary.

Answer: yes


Question: Question: This came up recently on programmers.SE, when someone (a Russian, presumably non-native English speaker) asked why we used the term "sister sites", instead of "brother sites". Of course, I'm a native English speaker, and I have no idea either, hence this question. The full question, for context, was "Several of our sister sites have taken to featuring Questions [...]". It does seem odd, considering that English (usually) uses masculine terms as the default. 
Answer: It is because only female carries the direct increase/multiplication through reproduction; that's why we also say mother tongue.

Answer: no


Question: Question: I debated with my peers that we can use the word emails when referring to more than one and it would be grammatically right. But most of them said since we don't say we received mails today, similarly we won't say we received emails . Quick advice please. 
Answer: Dan Bron's comment (above) that e-mail/email at its inception was treated as a mass noun is correctand so is Kristina Lopez's comment (above) that e-mail/email is widely applied today not just to the medium of electronic mail but to individual messages sent and received in that medium. For many years the technology magazines where I worked enforced a strict house rule: e-mail (and later email) referred to "electronic mail" as a mode of communication, and individual messages had to be termed "e-mail [or email] messages." But three or four years ago, the overwhelming weight of popular usage prevailed, and we began to accept the use of email as a singular noun that could take an indefinite article, and emails as a plural nounboth referring to individual messages. It is probably not coincidental that other forms of electronic communication receive similar treatment in popular (and some publishing) usage: a text and texts for "a text message" and "text messages," respectively; and an IM and IMs for "an instant messaging message" and "instant messaging messages" (as I recall, people used to avoid "instant messaging message" by conflating the technology with the individual message to produce "instant message"). At publishing houses, the proper handling of "an e-mail [or email]" versus "an e-mail [or email] message" remains a house style issuethere is no universally agreed-upon preference. If you are beholden to no one's style guide, you are free to use the wording that you like better. But the overall tendency, I believe, is toward accepting an email and emails as collapsed forms of "an electronic mail message" and "electronic mail messages.".

Answer:
no