Which feature in nonfiction helps readers locate the main idea?

• A. Table of contents
• B. Glossary
• C. Bold terms and captions
• D. Index

Answer: (C)

The main idea is found by noticing features that spotlight important ideas and explain what you’re looking at. Bold terms catch your eye and signal key ideas or vocabulary the author wants you to remember. When you see these bold words, you’re nudged toward the central points of the section. Captions under photos, charts, or diagrams explain what the image shows and how it connects to the text’s message. That connection helps you see the overall point the author is making, not just isolated facts.

So, bold terms and captions work together to guide you to the main idea by highlighting big ideas and clarifying how visuals support them. In contrast, a table of contents helps you find where topics are in the book, a glossary defines terms, and an index shows where to look for information, but none of these directly signal the section’s main idea.