What is the significance of 'central idea' versus 'topic' in informational text?

• A. Topic is the subject; central idea is the main point the author makes about that subject.
• B. Central idea and topic are synonyms.
• C. Topic is about details; central idea is about grammar.
• D. Central idea is a list of facts; topic is the subject.

Answer: (A)

The main idea being tested is understanding how central idea and topic relate in informational text. The topic is the subject of the writing—the broad thing the text is about. The central idea, on the other hand, is the main point or message the author wants to convey about that subject. It’s the claim the text develops and supports with evidence, examples, and details, not just a list of facts about the subject.

For example, if the topic is a discussion of renewable energy, the central idea might be that switching to renewable sources reduces pollution and helps sustain the environment, and the rest of the text would provide evidence and examples to support that point. That’s why the correct choice describes the topic as the subject and the central idea as the main point the author makes about that subject.

The other options mix up these roles or mischaracterize central idea. Central idea and topic aren’t synonyms, because one is the subject and the other is the author’s primary message about that subject. The central idea isn’t about grammar, nor is it simply a list of facts; it’s a claim that ties together the details in the text. When you read, look for the one idea that everything in the passage supports—that’s the central idea about the topic.