Each of the following sentences has been divided into

Solution

The error is a dangling modifier. The sentence begins with the infinitive phrase "To understand the failure of the uprising" (part a). Grammatically, the subject of the main clause that immediately follows must be the logical "doer" of that action. However, the subject introduced in part (b) is "numerous primary sources." Since primary sources do not have the ability to "understand" an uprising, the modifier is left dangling. To correct the sentence, part (b) should be rewritten in the active voice to introduce a logical subject, such as: "...historians examined numerous primary sources." Correct structure: To understand the failure of the uprising, historians examined numerous primary sources, revealing contradictions in leadership decisions and public mobilisation strategies.