I dont have a clue
Indicate is a verb.
Some verbs indicate existence.
"About" is a preposition. It is commonly used to indicate the topic or subject of something, or to show the relationship between two things in a sentence.
Verb.
subject
All subjects are part of speech for they are all nouns.
A question mark is a punctuation mark, not a part of speech. It is used at the end of a sentence to indicate that it is a question.
A verb.
Adjective. Logic is the noun.
subject
A verb.
Sky is a noun. It can be use as a subject.