What’s the main idea of this passage?

(单选题)58. （ ） (单选题)57.（ ） (单选题)56. （ ） (单选题)Which of the following would be the best title for the passa (单选题)What does the passage imply? (单选题)How does the author feel about the solutions to problem of r (单选题)What is the main purpose of the passage? (单选题)It can be inferred from the last paragraph that the chemical (单选题)According to Jennifer DeBruyn, the next step of the study is (单选题)What can we learn about the worms in the study?