A scientist observes that when she opens the back door of her house to let her cat out, the songs of a certain species of bird abruptly change. She wants to follow up on her observations with an informal experiment. Which of the following is the best hypothesis for explaining the birds’ song changes?A. The bird species switches from song to warning call whenever it sees a potential predator. B. The bird species has a variety of songs that it sings, regardless o what is happening in its environment. C. The scientist is mistaken and the songs do not change. D. The bird species switches from song to warning call whenever it sees a potential predator.

1. seamount a raised footwall block between normal fault creates this 2. syncline break between rocks where a hanging wall rises relative to a footwall 3. hot spring on rolling hills, this a dip between hills 4. volcanic neck created when a block with hanging walls slips down between normal faults 5. caldera underwater volcano that never reaches above sea level 6. horst natural hot water on earth's surface containing many minerals 7. graben underwater volcano whose top is eroded flat by waves 8. crater less than a mile in diameter; looks like a bowl at the top of a volcano 9. guyot magma that filled the central vent that remains after the volcano has eroded 10. reverse fault over 1 mile in diameter; looks like a bowl over a volcano