Answer:
The USA became involved in Vietnam because it feared the spread of communism. The USA were unable to defeat the Vietcong and were met with growing opposition to the war back home.
this is the only one I can answer, I'm sorry. I hope this helps though
C . Central Chile , it rises in the northwestern foot hills
Answer:
I belive the answer is C It protects the earth from solar radiation
The local workers become redundant at their work-place and are soon retrenched,they lose their jobs