According to the passage, when a piece of space junk falls back to Earth is most dependent upon the--
O size of the object
O length of time it has been in orbit
O speed at which it was launched
O altitude of the object's orbit

if you want me to check your answer i agree with what you put. i read the story

answer: the sentence in the text that contains both the topic and the author's single most important idea about the topic

explanation: aww pineapple so adorable

remember, the goal of an adjective clause is to add more information to a noun or a pronoun. as you can see from the examples above, you can add information by including a longer adjective clause or tighten up a sentence by turning the adjective clause into an adjective phrase.