Fisrt one is biological. Both parts of her maintain them selves independently. After months of being severed, Vera's top; Blackberry grew larger tits for engery storage, smaller organs developed in her chest and then also formed a small pussy for waste.
Razberry, her butt, obviously now incapable of pregancy uses her womb as a her stomach for an all liquid diet absorbing water, sugar, and vitamines into her blood stream. With no brain or upper body to need O2, Raz... rarly ever having to pee because of less to process, uses her kidneys as O2 CO2 exchange locations and bladder as a lung.
2 different girls, with all senses and would only be mildly sad if one were to die.