Question ID:PT84 S3 Q2 Passage:The Common Loon is a migratory bird that winters in warmer regions and returns to its breeding lakes in the spring. Typically, only one pair of loons occupies a single lake. Breeding pairs in search of breeding territory either occupy a vacant lake or take over an already occupied one. Surprisingly, almost half the time, returning loons choose to intrude on a territory already occupied by another pair of loons and attempt to oust its residents. This happens even when there are vacant lakes nearby that are perfectly suitable breeding territories. Stem:Which one of the following, if true, most helps to explain the surprising behavior described above? Correct Answer Choice:DChoice A:Most of the nearby vacant lakes have served as successful loon breeding territory in the past. Choice B:Contests for occupied breeding territory may be initiated either by male loons or by female loons. Choice C:Loons that intrude on an occupied breeding territory are successful in ousting its residents about half the time. Choice D:Loons frequently determine that a lake is a suitable breeding territory by observing the presence of a breeding pair there. Choice E:Lakes that are perfectly suitable for loon breeding have fish for food, a site for a nest, and a sheltered area to rear chicks.