Benjamin Franklin was a prolific inventor. He invented the lightning rod, the Franklin stove, studied electricity, discovered the Gulf Stream, started the first library, and on and on. Among his many other inventions, what musical instrument did he invent?
Options: the intensity of light emitted by them changes with time, the distance of the stars from the earth changes with time, the refractive index of the different layers of the earth's atmosphere changes continuously, consequently the position of the image of a start changes with time, the light from the star is scattered by the dust particles and air molecules in the earth's atmosphere
Options: international agreement signed in 1947 between non-communist nations with the object of encouraging international trade unobstructed by tariff barriers, agreement which seeks to achieve its aim by arranging and encouraging bargaining with trade concessions between members, Both option A and B, None of the above
The Latin word formica means ant. The name formic acid is derived from this Latin word because
Options: this acid, in ancient times, was used to eliminate ant-hills, this corrosive acid is secreted by ants to drive away their enemies, this acid was first obtained by the distillation of ants, ants are attracted by the odour of this acid