18. According to the passage, when was a U.S. patent issued for envelopes?
Your Answer is
Correct Answer is G
Explanation
According to the title stem location word USpatent, L52 can be located. The first letter of U.S. patent protection appeared in 1849. Item G is in line with the meaning of the question.
Item G: Adhesive postage stamps appeared in 1840.
Item F: The first postage stamp in Great Britain was in 1840.
Item H: Registered mail first appeared in 1956.
J item: street drop boxes appeared in London in 1855.