Answer:
The subject is "issues" and the verb is "include". The correct answer is A.
Explanation:
As we know, the subject of a sentence is its topic, what the sentence is about. In the structure "Issues considered worthy of debate include health insurance and the environment", the topic of the sentence - its subject - is the plural noun "issues". Basically, the sentence is giving us information about certain issues.
A verb is a word that expresses an action or a state. It is part of the predicate and helps introduce the information about the subject. It agrees with the subject, that is, if the subject is plural, the verb is also plural. The verb "include" has such relationship with the subject "issues". Thus, the best answer is letter A.
