Whistles could also be used to communicate between adult dolphins and baby dolphins.

参考答案:

A解析：问题中的关键词是adult dolphins和baby dolphins。对应原文第四段第一句，“We are building up a catalogue of the different whistle types they use and trying to associate them with behavior. like foraging，resting，socialising and the communications of groups with calves．”说科学家正在设