Due to Bio Suits being made from their own bodily tissue, it can transform and grow along with its wearer via Transforming Ability. Should their artificial clothing be removed (either due to damage in battle, by powering up, or removed at the wearer's discretion) the Bio Suit underneath remains until it is replaced by newly grown clothing.
Even when wearing artificial clothing like Battle Armor, members have a Bio Suit underneath regardless of what they are wearing (basically acting as a form of undergarment). These natural clothes can be removed at will or replaced with newly grown clothing. Even when it seems as though a member of Frieza's race is unclothed, they are generally wearing Bio Suits. Members of Frieza's race possess the unique ability to grow their own clothing and armor from their own body tissue. Frieza's Golden color Bio Suit of his Ultimate form