Dear azadeh
there was an error specially a grammatical error in ur comment so i see its better to solve it for u
"Life" and "lives" are singular and plural, so it comes down to an agreement issue. Singular is supposed to stay consistent with singular antecedents and verbs; and plural is to stay consistent with plural as well. Even though we hear it wrong all of the time
thus you should use lives
tnx for ur comment