Could you explain about the "debated ideas"? What does it mean?
"Most debated ideas" here means it is an idea that is highly debated over, as what can be considered the correct answer is vague and undecided. When the speaker says "most debated ideas," he means that the idea of "risky" playgrounds is a topic that is hotly contested by many people. You can also use the word "controversial" to express the same idea. Ex: What came first, the chicken or the egg? This is one of the most debated ideas around the world. Ex: Our debate team has a tendency to represent controversial ideas.