Read the passage.

For years, adults have been telling children, "Go outside. The fresh air will do you good." It turns out that there's a scientific basis for this. But it's not just the air that's so important. It's the sunlight. While sunlight has many benefits for plants, it also has benefits for people.

The writer should revise the passage to add concrete details that answer what question?

What are the benefits of sunlight for plants?
What are the benefits of sunlight for people?
What are the benefits of fresh air for plants?
What are the benefits of fresh air for people?