Which of the following boxes are placed in the lowermost shelf?

Study the following information carefully and answer the questions given below. Ten boxes viz. Q, R, S, T, U, V, W, X, Y and Z are placed one above the other in five different shelves of two different stacks viz. Stack 1 and Stack 2, but not necessarily in the same order. Stack 1 is to the west of stack 2. The lowermost shelf is numbered as 1 and the shelf immediately above it is numbered as 2 and so on. X is placed even numbered shelf of an even numbered stack. The number of shelves above X is one more than below U, where both are placed in different stacks. Q is placed between U and S but in the same stack as X and different to S which is placed two shelves above U. V is placed in the topmost shelf and immediately above W in different stacks. The position of V with respect to X is the same as the position of Q with respect to T. Neither R nor Y is placed in the same stack as T. R is placed immediately below Z but does not below Y.