Which of the following functions of hydrogen is not mentioned in the passage?

(单选题)Which is not the advantage of the author’s daily walking? (单选题)What can we know about the author? (单选题)What is the author’s occupation besides her full-time job? (单选题)What does the writer think about fitness gadgets? (单选题)According to Doctor Daniel Kraft, ______. (单选题)What does the second paragraph talk about? (单选题)The underlined phrase “obsessed with” in the first paragraph (单选题)What’s the meaning of the underlined sentence? (单选题)Which of the following statements is TRUE? (单选题)We should thank our parents because ______.