TASK DEFINITION: In this task, you are given a sentence from the research paper and your task is to classify the given sentence into the following categories: Background (Why is this problem important? What relevant works have been created before? What is still missing in the previous works? What are the high-level research questions? How might this help other research or researchers?), Purpose (What specific things do the researchers want to do? What specific knowledge do the researchers want to gain? What specific hypothesis do the researchers want to test?), Method (How did the researchers do the work or find what they sought? What are the procedures and steps of the research?), or Finding (What did the researchers find out? Did the proposed methods work? Did the thing behave as the researchers expected?). 
PROBLEM: The profile of the fecal bacterial microbiota was compared using 16S amplicon sequencing.

SOLUTION: method

PROBLEM: which could bind the HR1 or HR2 region of fusion protein , respectively.

SOLUTION: method

PROBLEM: A lot of structurally diverse coumarins analogues were found to display remarkable array of affinity with the different molecular targets for antiviral agents and slight modifications around the central motif result in pronounced changes in its antiviral spectrum.

SOLUTION:
background