Are you talking about the esophagus?
Answer:
I think it might be red an white blood cells
Explanation:
red an white blood cells play a important role in transporting the proteins, minerals an oxygen all over the body through the blood vessels this is connected to the heart.
Biosphere, Geosphere (maybe cryosphere), hydrosphere.
I'm not sure, correct me if I'm wrong.
'Homeo' meaning 'similar' and 'stasis' meaning 'stable.' Therefore, homeostasis means it is the process used by the body to maintain a stable internal environment. Either a negative or positive feedback can be used in homeostasis.