Consider the following spontaneous cell reactions: 
X + Z²⁺ → X²⁺ + Z
Y + Z²⁺ → Y²⁺ + Z
X + Y²⁺ → X²⁺ + Y
Sort the following reduction half-reactions in decreasing order of likelihood of occurrence:
(1) X²⁺ + 2 e^– → X
(2) Y²⁺ + 2 e^– → Y
(3) Z²⁺ + 2 e^– → Z