Final answer:
Biologists' ability to analyze bird calls for research suggests that people can similarly train to identify frog calls.
Step-by-step explanation:
The best line that supports the idea that people can train themselves to identify frog calls is mentioned in the context of a research scenario: "Biologists analyzed the sound frequencies of different calls made by a small bird species". This indicates that through systematic study and analysis, biologists can discern the various calls made by animals, such as birds, which implies that a similar approach could be used for identifying frog calls. It shows that understanding animal communication, such as calls, can be achieved through careful observation and research, which can also apply to the training of individuals to recognize specific calls of fro