The submarine became a potentially viable weapon with the development of the Whitehead torpedo, designed in 1866 by British engineer Robert Whitehead, the first practical self-propelled or 'locomotive' torpedo.[20] The spar torpedo that had been developed earlier by the Confederate States Navy was considered to be impracticable, as it was believed to have sunk both its intended target, and probably H. L. Hunley, the submarine that deployed it. In 1878, John Philip Holland demonstrated the Holland I prototype.
Discussions between the English clergyman and inventor George Garrett and the Swedish industrialist Thorsten Nordenfelt led to the first practical steam-powered submarines, armed with torpedoes and ready for military use. The first was Nordenfelt I, a 56-tonne, 19.5-metre (64 ft) vessel similar to Garrett's ill-fated Resurgam (1879), with a range of 240 kilometres (130 nmi; 150 mi), armed with a single torpedo, in 1885.
A reliable means of propulsion for the submerged vessel was only made possible in the 1880s with the advent of the necessary electric battery technology. The first electrically powered boats were built by Isaac Peral y Caballero in Spain (who built Peral), Dupuy de Lôme (who built Gymnote) and Gustave Zédé (who built Sirène) in France, and James Franklin Waddington (who built Porpoise) in England.[21] Peral's design featured torpedoes and other systems that later became standard in submarines.[22][23]
The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The civil war tested the foundation of a country that uses democracy in that the civil war confronts people from the same country on the battlefield for political and economic reasons.
It is hard to believe that people from the same nationality -brothers we could say in a metaphorical way- confront each other to the extreme of seceding from the Union and fight using weapons. A civil war is an internal battle that hurts democracy and the legitimacy of the government that the founding fathers so carefully planned for the United States since colonial American times.
A civil war separates, divides. As President Abraham Lincoln said in his famous speech "A House divided," if a country is divided from within, this not only hurts democracy and freedom but also impacts all aspects and foundations of a nation.
Answer:
It marked the turn of the tide for control maintained by the Nazi Germany less than a year after the invasion. Nazi Germany surrendered
