How did the reasons for russian and british interests in persia change?

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

that would be the steamboat because none of the other things are forms of transportation

it broke up the ottoman empire (just a small fact) and the turkish leaders lost many soldiers.