Question

an article about how recycling helps the planet focuses on the
lesson
central idea
focus
theme

Explanation:

To determine the answer, we analyze the options:

• "Lesson" refers to what is learned, not the main focus of an article.
• "Central idea" is the main point or message of a text. An article about how recycling helps the planet has a central idea (the main concept it conveys about recycling and the planet).
• "Focus" is more about the specific area of study, but here the article's main point is its central idea.
• "Theme" is a broader concept (like environmental protection), while the article's specific message about recycling helping the planet is the central idea.

Answer:

Central idea