Question

tornadoes do not last long. the damage they cause can be serious. but so ← joining words revise your work. so helps give a reason why, but neither of these ideas causes the other. which joining word helps show that the two ideas are opposite?

Explanation:

The word "but" is a coordinating conjunction used to show contrast between two ideas. Here, the short - duration of tornadoes and the serious damage they cause are contrasting concepts. "So" is used to indicate a cause - and - effect relationship, which is not applicable here.

Answer:

but