The subordinate clause in this sentence is because I forgot to buy milk. The whole sentence is used as an adverb. Adverbs are used to answer questions such as where, when, or in this case, why.
Why did I have root beer in my cereal? Because I forgot to buy milk.
Answer: The first passage of the story is about the history of formation of the Yellowstone National Park, this includes the information why it is significant, which means that author appeals to readers' emotions, describing the park with great interest and passion. The second passage has no mood, just contains some facts and statistics which would have a less appealing factor to the reader.
Explanation:
So all you have to do is write in the second column what you know. The third is for your conclusion, or your answer