If I remember correctly the opium wars resulted in china being figuratively split up by european powers. So, I'd go with 4.
Answer:
involvement in the Spanish-American War
Explanation:
Answer:
3. 3-D Printing.....You probably didn’t know that what’s now known as 3-D printing began in the early 1980s with a process called selective laser sintering. University of Texas alum Carl Deckard began inventing the process, commonly referred to as SLS, while he was still a graduate student.
Explanation:
If you are talking about the first air pollution problem its is A, almost about 100 years ago.
1955
