What is the full meaning of DNC​

Based on context, the word “insoluble”most likely means?

How does the poem's mood and tone change in each of these stages of “o captain! my captain! ” by walt whitman? (i need an answer asap )

Lauses unnecessary to the meanings of the words modified demonstrative 2. clauses necessary to the meanings of the words modified relative 3. words for which pronouns stand intensive 4. a pronoun ending in -self and referring to the previously used noun or pronoun nonrestrictive clauses 5. a pronoun ending in -self and used for emphasis restrictive clauses 6. pronouns that ask questions indefinite pronouns 7. pronouns that point out to whom or to what the speaker is referring reflexive 8. everyone, nobody, and something are examples antecedents 9. pronouns introducing adjective or noun clauses interrogative 10. i, you, him, mine, and their are examples personal pronouns