body systems -k8凯发

1. digestive
   1. mouth
   2. sophagus
   3. stomach
   4. intestines
2. circulatory
   1. heart
   2. veins
   3. arteries
   4. capillaries
3. respiratory
   1. nose
   2. lungs
   3. trachea
4. nervous
   1. brain
   2. spinal cord
   3. nerves