Question 21

In order to train dogs to listen to your commands, you must set up a system that rewards their positive responses.

This sentence clearly establishes a topic that can be elaborated upon in an explanatory essay. It introduces a specific subject—dog training—and implies a methodical approach that can be further explored.

A) Even though mobile phones are seen as more convenient, there are many advantages to maintaining a landline.

While this sentence presents a comparison between mobile phones and landlines, it lacks a clear focus on a specific topic for explanation. Instead, it suggests a debate rather than a straightforward explanatory premise, making it less suitable for starting an explanatory essay.

B) It always calmed my nerves when my father sat on the back porch drinking tea from a flowered mug and humming 'Old Man River.'

This sentence is more anecdotal and personal, focusing on a sentimental experience rather than providing a clear topic for explanation. It does not set the stage for an informative discussion and is thus not appropriate for an explanatory essay.

C) Negative political ads should not be not used in campaigns because they fail to give the public any reliable evidence about candidates.

Although this sentence presents an argument against negative political ads, it is more suited for a persuasive essay than an explanatory one. It does not focus on explaining a concept but rather advocates for a position, which diverts from the goal of providing an explanation.

D) In order to train dogs to listen to your commands, you must set up a system that rewards their positive responses.

This option offers a clear instructional approach, making it ideal for an explanatory essay. It invites elaboration on the methods of dog training and the principles of positive reinforcement, which can be effectively expounded upon in the body of the essay.

Conclusion

The correct answer, D, is the most suitable choice for beginning an explanatory essay as it clearly outlines a topic that invites detailed exploration. The other options either present opinions, personal anecdotes, or arguments that do not lend themselves to a straightforward explanatory format. Thus, option D stands out as the only one that effectively sets the stage for a comprehensive explanation.