Final answer:
The question is related to the invention of the telephone by Alexander Graham Bell in the early 19th century. The term 'G. Bell' refers to Alexander Graham Bell who invented the telephone, making significant strides in communication technology.
Step-by-step explanation:
The subject of this question refers to a notable event in History, specifically the invention of the telephone. The sentence is regarding the significant contribution of Alexander Graham Bell, a renowned scientist, and inventor of the 19th century. A Scottish-born scientist, engineer, and innovator, Bell, is most famous for his pioneering work on the development of the telephone.
In the early 1870s, Bell focused on inventing devices that would help transmit speech. After much experimentation and trials, he finally was successful in transmitting a voice message to his assistant Thomas Watson in 1876. This is considered as the birth of the telephone. Despite challenges, Bell's invention stood successful over time. Therefore, Bell is rightfully called the inventor of the telephone.
Essentially, filling in the blank in the question, it becomes 'In the early 19th century, G. Bell, a great scientist, invented the telephone for man.'
Thus the final answer in two lines would be: The subject of the question refers to the historical invention of the telephone, where G.Bell denotes Alexander Graham Bell. The blank can be completed as 'invented.'
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