The bladder.
Bladder
Amniotic sac
Amniotic sac
The urinary bladder
Marsupial sac.
It's an Air Sac.
The bladder.
the stomach
Bladder
Amniotic sac
Amniotic sac
I Think You Thinking Of The Alveoli/Alveoli's
gallbladder
Pancreas.
The scrotum protects the oval-shaped testicle.
The Stomach