How many nerves does the brain have

What came first egg or chicken? and is tomato a vegetable or a fruit?

Adigestive system that is a series of tubes beginning at the mouth and ending at the anus is a digestive system.

An example of internal feedback working to maintain homeostasis is your a. decreased respiration rate when you are studying b. decreased heart rate when you are sad c. increased respiration rate when your muscles need more oxygen d. increased heart rate when your lungs need more oxygen