How to find the Main Idea

The TOPIC is what the passage is about (one or two words). The MAIN IDEA is what the passage SAYS about that topic (a full sentence). The right answer is always the second.

Look at the first sentence and the last sentence. The main idea is usually announced near the start and reinforced or modified near the end. If a choice only fits part of the passage, it's a detail, not the main idea.

Two patterns: (1) too narrow — describes one paragraph only; (2) too broad — describes a topic the passage merely mentions. The right answer fits the WHOLE passage and is provable from it.