Hey. In my opinion, the answer is obvious. Take for example, the dollar, if the value of the dollar changes, then other currencies change their course.
it's hard to realize how the valuation of a dollar change because it's still 1 dollar in anyway but we can only realize it when we compare it with others like 1 dollar used to be equal 0.8 euros, but now it's 0.9 so dollar is increasing the valuation.