Answer: The United States had taken possession of the Philippines (as well as Guam and Puerto Rico) in 1898, after winning the Spanish-American War. Thus US interest in Asia was heightened.
At the same time, other nations had begun competing for "spheres of influence" in trade access with China.
Further detail:
The Open Door policy was issued by the United States in 1899-1900 as a series of dispatches from the US Secretary of State to other nations that had trading interests in China -- Great Britain, Germany, France, Italy, Japan, and Russia. The policy reasserted earlier agreements that all countries should have equal access to ports in China, without undue preference to "spheres of influence" for one nation or another. The United States was seeking to maintain an equal footing with other nations in the access to trade in China.
Under the articles of confederation, if Virginia had ten thousand citizens and Delaware had five thousand citizens, then the number of representatives that Virginia and Delaware would have is 2. For every state having less than 30 thousand citizens, the number of representatives would remain the same.
The unit is called a newton (kg.m/sec2), written as NT or N.
When you strip away the buzzwords and memes that conservatives often give progressive policies, what you find is that the majority of Americans actually like them.
The answer is letter d. Thomas Malthus. He believe that if population were to grow
unchecked it would lead to famine and low food production. He wrote about in this in his work Malthusian
Catastrophe. He later added that this
would not lead to catastrophe but it would limit the growth of population.