Human nature- human nature is very closely related to both pride and prejudice, (prejudice when broken down is related to bias and judgement), which- again- are related to human nature. marriage COULD be related to human nature, but it would be very hard to relate. Human nature is often related as a theme because it's tied to many themes- just a little less straightforward than most themes. Hope this helps!
It is
a
a
a
b
b
b
that the rhyme pattern