"Had better" is always followed by the base form of the verb without "to". "Had better taken" uses the past participle correctly in this structure to express advice or recommendation.

"Interfering with mail" means unlawfully handling or meddling with it. "Tampering" is the most precise replacement, meaning to interfere with something in a way that causes damage or is illegal.

"Menace" means to threaten or pose danger to someone. The correct replacement is "Threaten", which carries the same meaning in this context about monkey behavior.

"Disarming candor" means an openness so genuine and charming that it removes hostility or suspicion. This perfectly fits the context of an applicant winning over skeptical interviewers through honest and natural responses.

A Doctor works at a Hospital as their primary workplace. Similarly, a Professor works at a College. Both pairs show a professional and the institution where they perform their work.

The correct rearrangement is: "Science has found a remedy to almost every disease." This places the subject (Science) first, followed by the verb and object in logical order.

In indirect speech, questions are reported using "asked". "Will" changes to "would" in reported speech, and pronouns are adjusted. The correct form is: "My friend asked me if I would take him to his office."

"Synchronized" means occurring at the same time in a coordinated manner. Its antonym is "Arrhythmic", which means lacking rhythm, regularity, or coordination.

"Animosity" means strong hostility or hatred toward someone. "Enmity" is its closest synonym, also meaning deep-seated hatred or ill will between people or groups.

"Complement" means something that completes or enhances something else. Morality complements human development by completing it. "Compliment" means praise, which does not fit here.