Where should I write "no" in the article? Why? See the supplementary question for details.

It should be placed in place A, because if it is placed in place B, it means: then the earth may not be our only home, and we have to re-examine the relationship between human beings and the earth.

If the earth is not the only home, how will people review the relationship between human beings and the earth? The answer must be that the earth's environment is no longer important, and there is no need to give up the economy to protect the environment. Industrial sewage, toxic gases and deforestation will eventually lead to the disappearance of the earth.