Answer:
1. Boundary is the subject
2. is - verb
3. edge - subject complement
Explanation:
(The linking verb is (i.e., the verb to be). The subject complement identifies the subject boundary.
In understanding the central idea or the main idea of a particular passage. You must take out the hard terms and look for their meanings. It is one way of understanding at the same time learning with the passage. It is also advisable to stay focus on what you are reading to easily understand it.
