All other variables such as exchange rates are held constant allowing us to focus on the factor we are trying to isolate. For each variation, consider the implications on the current account. Higher domestic growth rates, increases our incomes and consumption of goods and services, including imports. A rise in the domestic inflation rate, holding foreign inflation rates constant, implies there are relatively higher prices for domestically made goods and makes imports cheaper in comparison since their prices have not changed - we are holding them constant. Higher domestic interest rates increase the attractiveness of our nation's financial assets to foreigners as they can earn a relatively higher return by sending their money abroad.
Exchange rates deal with the value of one currency in terms of another.
From the opposite perspective, a dollar buys eight pesos, used to purchase Mexican goods and services. A devaluation in the currency lowers one currency's value in terms of the other. In this case the peso has depreciated. If a coke costs a dollar, the price for the Mexican consumer has increased from four to seven pesos, while it still costs a dollar for the U.S. consumer. In this example the dollar has appreciated in relation to the peso.