False negative is a condition when you got a negative result for a specimen which was positive. To prevent false negative occur, first you need to use golden standard test or a test with high specificity. You can do multiple tests to ensure the specimen is negative and using a positive control to make sure the reagent is still working fine.
To contract and churn the food to break it down into smaller molecules
3 is the correct answer. Let me know if you want me to explain why that is the answer.
The answer should be equator