Question

correct the text by inserting two commas. (note: in this skill, serial commas are not optional.)
smallpox is a dangerous disease true but should the only existing samples of the smallpox virus be destroyed?

Explanation:

The parenthetical phrase "true" interrupts the main clause, so it needs commas on both sides to set it off correctly. This clarifies the flow of the sentence, separating the introductory statement from the contrasting question.

Answer:

Smallpox is a dangerous disease, true, but should the only existing samples of the smallpox virus be destroyed?