explain and/or show work

The pumping lemma for CFLs writes a long enough string in the language in five parts UVXYZ and requires that |vy| greaterthanorequalto 1. This requirement can be enforced because in the proof of the pumping lemma: The start variable in the grammar does not appear on the right hand side of any rules. The grammar has no epsilon-rules except perhaps from the start variable. The grammar has no unit rules. The grammar has no rules with both terminals and variable on the right hand side. The grammar has at most two variables on the right hand side of every rule