Answer:
Step-by-step explanation:
a. The topic sentence is the first sentence: "Seoul, the capital of Korea, is old but modern, and populated."
b. The controlling idea is that Seoul is a city that combines ancient and modern features and is a popular tourist destination.
c. The topic sentence is followed by several major support sentences that provide specific information about Seoul as a city, including its ancient palaces, modern skyline, and efficient transportation system. These sentences all support the controlling idea that Seoul is a city that combines the old and the new and is a popular tourist destination. The final sentence is a minor support sentence that provides additional information about the city's population, which reinforces the idea that Seoul is a thriving and energetic city.
d. A possible concluding sentence for the paragraph could be: "Whether you're interested in ancient history or modern culture, Seoul has something to offer everyone, making it a must-visit destination for any traveler."