It's pretty undeveloped and the climate isn't favorable for some people to live in. If more cities were built and stores to provide for our needs, the population would likely increase.
The correct answer is A. The expansion of international trade.
Explanation
In the photographs you can see two photographs of Hong Kong, the first is from 1910 and the second from 2000. The first photograph shows the coast of Hong Kong with few buildings and boats, while the second photograph shows large buildings and boats. This difference between the two photographs denotes that there was great growth in the city. Hong Kong's growth is because it is a special administrative region that has a free market economy that has allowed this city to be at the epicenter of world trade and economy. Therefore, the correct answer is A. The expansion of international trade.
The sky is blue because blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
You need an image. Do you mind telling me the question?