Final answer:
Iago tells Desdemona that Othello's anger is due to state business, misleading her as a part of his manipulative plot.
Step-by-step explanation:
When Desdemona first starts to realize that Othello is angry with her, Iago attempts to allay her fears by suggesting that Othello's ill temper is due to some troubling thoughts about state affairs. Iago implies that Othello's mood has nothing to do with Desdemona herself but is instead related to the weight of political and military issues that are on his mind. This deception is part of Iago's manipulative scheming throughout the play.