Peter Cetera 's tenor voice complimented the baritones of his bandmates Robert Lamm and Terry Kath .
Cetera shared lead vocal on three of the eleven songs on the album - `` Question 67 and 68 , '' `` I 'm a Man '' < ref > { { Cite album-notes|title= Chicago Group Portrait ( Box Set ) |year=1991The follow-up album , Chicago , vaulted the band to popular status throughout the world .
Peter Cetera