Which of the following did samuel morse invent or improve?

-the light bulb
-the airplane
-the telegraph
-the telephone

Samuel Morse invented the telegraph.

Samuel Morse was an American inventor and painter who, together with his associate Alfred Vail, invented and installed a telegraphy system in the United States, the first of its kind. It was the Morse telegraph, which allowed messages to be transmitted by electrical pulses encrypted in the Morse code, also invented by him.

On January 1, 1845, Morse and Vail inaugurated the first telegraph line in the United States between Washington and Baltimore, which used its telegraphy system.