Answer:
I'd say the telegraph.
Explanation:
Developed in the 1830s and 1840s by Samuel Morse (1791-1872) and other inventors, the telegraph revolutionized long-distance communication.
Answer:
the chemicals had to be applied to the plate in the dark.
the photograph had to be made and developed while the chemicals were still wet
During WW2 the military was inventing the atomic bomb then later launched it on Japan
