There has, however, been interest among railroad operators in returning to DC use at higher voltages than previously used. At the same voltage, DC often has less loss than AC, and for this reason high-voltage direct current is already used on some bulk power transmission lines. DC avoids the electromagnetic radiation inherent with AC, and on a railway this also reduces interference with signalling and communications and mitigates hypothetical EMF risks. DC also avoids the power factor problems of AC. Of particular interest to railroading is that DC can supply constant power with a single ungrounded wire. Constant power with AC requires three-phase transmission with at least two ungrounded wires. Another important consideration is that mains-frequency 3-phase AC must be carefully planned to avoid unbalanced phase loads. Parts of the system are supplied from different phases on the assumption that the total loads of the 3 phases will even out. At the phase break points between regions supplied from different phases, long insulated supply breaks are required to avoid them being shorted by rolling stock using more than one pantograph at a time. A few railroads have tried 3-phase but its substantial complexity has made single-phase standard practice despite the interruption in power flow that occurs twice every cycle. An experimental 6 kV DC railway was built in the Soviet Union.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Which type of power does require three-phase transmission?
Ah, so.. AC

Working with photographer Steven Klein, Madonna completed a 17-minute film called secretprojectrevolution. The BitTorrent company was selected by Madonna to release the film as part of a Madonna bundle. It was released on September 24, 2013, and consisted of the 17-minute film, its stills, a Vice interview, and a message from Madonna. With the film she launched the Art for Freedom initiative, which helped to promote "art and free speech as a means to address persecution and injustice across the globe". The website for the project has had over 3,000 art related submissions since its inception, with Madonna regularly monitoring and enlisting the help of other artists like David Blaine and Katy Perry as guest curators.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What initiative did Madonna launched with her film?
Ah, so.. Art for Freedom

The Continental Army was created on 14 June 1775 by the Continental Congress as a unified army for the colonies to fight Great Britain, with George Washington appointed as its commander. The army was initially led by men who had served in the British Army or colonial militias and who brought much of British military heritage with them. As the Revolutionary War progressed, French aid, resources, and military thinking influenced the new army. A number of European soldiers came on their own to help, such as Friedrich Wilhelm von Steuben, who taught the army Prussian tactics and organizational skills.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): When did Friedrich Wilhelm von Steuben teach Prussian tactics?
Ah, so..
unanswerable