I believe that answer is a because it has opposite reactions.
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
The weather of the savanna biome is torrid wet and a dry climate.
Hope this Helps!
