Which elements of this author’s purpose indicate that the author should use a cause and effect essay structure? John studies the habits of birds in his hometown. He recently noticed that these birds are avoiding a certain part of town after a new factory opened there. He wants to publish his findings examining the reasons for this unusual behavior in the town’s birds. His research focuses on whether the shifting pattern is caused by the new electric substation serving the factory. He’s also looking at whether noise played a role in the new pattern.