Answer :
ELECTRICITY.is mans best invention.thanks to edison..without it our life would be incomplete...helps us to do the basic things in our life...uses of electricity....advantages....save electricity
Language:
Among the ancient inventions, the invention of a Language and its script as a medium of communication is the most important invention. With out a means to express ones views either verbally or by means of writing, human beings would have been as good as the cave man.
The language made a person do some thing in a life time and pass it on to the next generation. The knowledge and culture gained by one generation became the starting point for another generation. Hence we progressed. We had books because we had a language to write. Without reading books, even the great scientists could probably not invent much.
The invention of language has allowed a person to think better, improve culture, further enabled many discoveries and inventions. Language enabled people to live together harmoniously and establish family and society life. A language is very essential for the development of a civilization.