Sorry to disagree but I think the answer is flower-tops. The poem is about nature yes but the term heads seems to refer to the flower-tops as the topic was daffodils. This is personification as if the daffodils were humans that could dance.
The EPA is the organization I don't know exactly what the scientists are called though. Hope I helped in some way.
Answer:
The Supernatural
Explanation:
The Romanticism Era of literature was pratically a polar opposite of the writing style of Realism, where Realism focused on simple plots, and easy to understand descriptions of life and the reality of the situation. Now Romanticism is very different, it focuses on the Supernatural and Strange side of life, and often had elaborate plots. Romanticism includes vivid descriptions of detail and has an elaborate plot, with a supernatural twist to it. For example a story of Romanticism is the Raven.
