Exposure to sunlight helps a person improve his health because
Options: the infrared light kills bacteria in the body, resistance power increases, the pigment cells in the skin get stimulated and produce a healthy tan, the ultraviolet rays convert skin oil into Vitamin D
Options: One of the important parties in USA, the political parties which has no definite principles, the political party which changes with the change in the times and circumstances in the country, All of the above
Options: the white UN Emblem is super-imposed on a light blue background, the red UN Emblem is super-imposed on white background, the light blue UN Emblem is super-imposed on white background, None of the above
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?