It is just something to modify or change the noun
While the main idea is usually in the first sentence, the next most common placement is in the last sentence of a paragraph. The author gives supporting information first and then makes the point in the last sentence. Here's a paragraph we can use as an example. Try to locate the topic and the main idea.
The correct answer here is C. The lines 'If good, why do I yield to that
suggestion Whose horrid image doth unfix my hair And make my seated
heart knock at my ribs, Against the use of nature?' most likely refer to
the theme that things are not always what they seem. This is
illustrated by the fact that the character is negating the fact that
something is good through referring to events that have unsettled them.
