Which of the following prefixes implies duplication when attached to a root word?

The word "crucial" is the only correct spelling and fits the context of the sentence.

This sentence has a subject ("Walking away") and a predicate ("was Deepak’s response"), forming a complete thought. The other options are fragments that do not convey a full idea on their own.

In this sentence, "slow" is used correctly to describe the student's writing speed, while "slowly" is an adverb describing how the student wrote.

A. Physics is a difficult subject to learn.

In this sentence, "Physics" (singular) is paired with the singular verb "is." This is a correct subject-verb agreement.

The other options have issues with subject-verb agreement:

B. "News travel fast" should be "News travels fast."

C. "The study of various sciences are compelling" should be "The study of various sciences is compelling."

D. "Measles usually spread through respiratory fluid" should be "Measles usually spreads through respiratory fluid."

The prefix that implies duplication when attached to a root word is "re-." For example, "redo" means to do again, indicating duplication of the action.

A capital letter is usedfor the first word of a sentence and for all proper nouns (words that name a specific person, place, organization, or thing). Capitalization in Dis used to indicate the organization and compared to other others that do not follow the requirements for using capital letters, it makes Dthe correct answer.