Ron has given a detailed explanation for this problem on the Nov 18, 2010 Study Hall (that was really helpful!), focusing on verb tense. I just have one question that is uncovered.
The first detailed study of magpie attacks in Australia indicates ...
I think "indicated" would make more sense than "indicates", since "indicates" means the action is not fixed in any particular timeframe but here we have "the first detailed study", which occurred in the past.
I'm not questioning the correct answer... just want to know how "indicates" work here. Thanks in advance.