Question: The key advantage of the four-rail system is that neither running rail carries any current. This scheme was introduced because of the problems of return currents, intended to be carried by the earthed (grounded) running rail, flowing through the iron tunnel linings instead. This can cause electrolytic damage and even arcing if the tunnel segments are not electrically bonded together. The problem was exacerbated because the return current also had a tendency to flow through nearby iron pipes forming the water and gas mains. Some of these, particularly Victorian mains that predated London's underground railways, were not constructed to carry currents and had no adequate electrical bonding between pipe segments. The four-rail system solves the problem. Although the supply has an artificially created earth point, this connection is derived by using resistors which ensures that stray earth currents are kept to manageable levels. Power-only rails can be mounted on strongly insulating ceramic chairs to minimise current leak, but this is not possible for running rails which have to be seated on stronger metal chairs to carry the weight of trains. However, elastomeric rubber pads placed between the rails and chairs can now solve part of the problem by insulating the running rails from the current return should there be a leakage through the running rails.
Is there an answer to this question: What is a key advantage to the fifth rail system?

Answer: unanswerable


Question: When a Teletype 33 ASR equipped with the automatic paper tape reader received a Control-S (XOFF, an abbreviation for transmit off), it caused the tape reader to stop; receiving Control-Q (XON, "transmit on") caused the tape reader to resume. This technique became adopted by several early computer operating systems as a "handshaking" signal warning a sender to stop transmission because of impending overflow; it persists to this day in many systems as a manual output control technique. On some systems Control-S retains its meaning but Control-Q is replaced by a second Control-S to resume output. The 33 ASR also could be configured to employ Control-R (DC2) and Control-T (DC4) to start and stop the tape punch; on some units equipped with this function, the corresponding control character lettering on the keycap above the letter was TAPE and TAPE respectively.
Is there an answer to this question: What two controls can be configured from a mobile phone?

Answer: unanswerable


Question: 1 STOBAR carrier: Admiral Flota Sovetskovo Soyuza Kuznetsov: 55,000 tonne Admiral Kuznetsov-class STOBAR aircraft carrier. Launched in 1985 as Tbilisi, renamed and operational from 1995. Without catapults she can launch and recover lightly fueled naval fighters for air defense or anti-ship missions but not heavy conventional bombing strikes.[citation needed] Officially designated an aircraft carrying cruiser, she is unique in carrying a heavy cruiser's complement of defensive weapons and large P-700 Granit offensive missiles. The P-700 systems will be removed in the coming refit to enlarge her below decks aviation facilities as well as upgrading her defensive systems.
Is there an answer to this question: When was Admiral Flota Sovetskovo Soyuza Kuznetsov first launched?

Answer: in 1985


Question: The Qur'an relates detailed narrative accounts of Maryam (Mary) in two places, Qur'an 3:35–47 and 19:16–34. These state beliefs in both the Immaculate Conception of Mary and the Virgin birth of Jesus. The account given in Sura 19 is nearly identical with that in the Gospel according to Luke, and both of these (Luke, Sura 19) begin with an account of the visitation of an angel upon Zakariya (Zecharias) and Good News of the birth of Yahya (John), followed by the account of the annunciation. It mentions how Mary was informed by an angel that she would become the mother of Jesus through the actions of God alone.
Is there an answer to this question: Who told Jesus that Mary would be the mother of Jesus?

Answer:
unanswerable