Fun window shopping in New York City: I. the topic lends to an informal style. As you may notice, the title is already informal, given the use of the word "fun". Also, a topic connected to shopping in New York city is related to leisure activities, that is informal situation.
Job opportunities in the computer programming field: F. it lends itself to a formal style. When talking about job opportunities, it usually makes reference to formal situations in which formal language is used.
What can schools do to lessen drug abuse? (including national statistics): F. considering this topic is probably intended to educators, including school personnel and teachers, the style should be formal. The fact that it includes national statistics entails it is a guide for the school to take specific actions. Therefore, it might have the status of an official document or something of the kind.
Some useful industrial plastics : F. Judging by the title, it seems a topic that should be treated seriously. Besides the wording in the title is formal.
Teaching children to play handbells: F/I. This one could either be Formal or Informal. It depends on the audience. It it is intended for parents or relatives, the style could be informal, but if it is for educators it should be more formal.
Fictional characters: villains we love to hate: F/I. Judging by the title, the topic could be treated in a formal more literary style, or informally, especially if it is intended for young students or adults without especific knowledge of literary terms.
Insulin: saver of lives.I. Judging by the style of the title, the use of "saver of life" suggests the topic is addressed to the general public, therefore the style should be more informal in order to facilitate understanding.
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