Answer:
1.got
2.would have take
3.had studied/would have passed
Placid means peaceful and tranquil.
The best synonym for placid would be C. peaceful.
Answer:
D. These scientists also believe that wind strength is unpredictable and wind energy can only be suitable to particular areas where the wind blows well.
Explanation:
That answer shows that wind energy is unreliable.
Hope this helps:)
I believe it is a categorical argument, however I am not sure.