TASK DEFINITION: In this task, you are given a sentence from the research paper and the category to which it belongs. Your task is to classify whether the given category is correct or not by providing "True" and "False", respectively. Here are the definitions for the 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: Sentence: BMDMs were cultured up to 21 days and used for infection study. 
 Section: method

SOLUTION: True

PROBLEM: Sentence: with basic reproduction number ( R 0 ) as the intermediate variable. 
 Section: method

SOLUTION: True

PROBLEM: Sentence: it is shown that a minimal functional element with hairpin forming potential is sufficient to down-regulate21 frameshifting activity. 
 Section: purpose

SOLUTION:
False