This is what I wrote (and it is not plagerized you can even check)
Explanation:
The sound that the narrator thinks he's heard at the end of the story is the old man's heartbeat but what he actually hears is his guilty conscious, because that is what is making him think that he can still hear the old man's heartbeat is that since he feels guilty about what he did his conscious is making it seem like the heart is still beating. In the text, it says that " I admit the deed-tear up the planks!-here, here! it is the beating of his hideous heart!" that shows how the narrator got tired of "hearing the heartbeat" so what he did was confess to what he did. The effect that the narration has on the story is that the suspense because in paragraph 17 we the audience are getting anxious because when the police arrive at the house were wondering at what time he will get caught.
subordinate clauses always start with a subordinating conjunction, and in this sentence, the conjunction is which. so the answer is "which had been lurking under the water"
