When two events (call them A and B) are Mutually Exclusive it is impossible for them to happen together: P(A and B) = 0. The probability of A and B together equals 0 (impossible).
Generation Z. Generation Z (also known as The Founders, Post-Millennials, the iGeneration, Plurals or the Homeland Generation) is the demographic cohort after the Millennials.
47, XYY syndrome (simply known as XYY syndrome) is caused by the presence of a single extra copy of the Y chromosome in each of a male's cells. 47, XYY males have one X chromosome and two Y chromosomes, for a total of 47 chromosomes per cell.