This is punctuated correctly.
"Marshmallows are my favorite snack" is a complete sentence unto itself.
The comma instead of a period shows that the sentence spoken is part of the whole sentence, which includes the speaker (she) and a word to describe how the speaker said it (explained).
Answer: what do you need help with?
Explanation: cougar is a wild cat.
Answer:
It illustrates how volcanic rock contributed to the formation of two islands at different times in the earth's history.
Explanation:
It doesn't talk about B and C, but D doesn't make sense either because that only occurred to the Hunga island.
the reindeer was very angry and grandmother because grandma didn't give her cookies. grandma died that night.
