Answer:
Simile.
Step-by-step explanation:
The sentence shown above is using the literary device called a simile. This feature allows the author of the text to make a comparison between two different things, which can present something related between them. In other words, the simile appears when it says that "one thing is like another thing,"
In this case, they can affirm that in the sentence shown in the question above, the simile was used in the expression "These neurohormones are like solvents".