Final answer:
The sentence that should be added to the very end of the paper is: 'The reality is that volcanoes present unique hazards, but volcanologists prepare for the unexpected in the field for the sake of helping people in those at-risk areas.'
Step-by-step explanation:
The sentence that should be added to the very end of the paper to bring it to an effective conclusion is:
The reality is that volcanoes present unique hazards, but volcanologists prepare for the unexpected in the field for the sake of helping people in those at-risk areas.
This sentence effectively restates the dangers involved in studying volcanoes and highlights the importance of volcanologists' work in mitigating the risks. It also connects back to the main theme of the essay, which is the hazards associated with volcanoes. This concluding sentence provides closure to the paper and leaves the reader with a strong reminder of the significance of studying volcanoes.