How is the circulatory system similar to a road-and-highway system?

The circulatory system is similar to a road & highway system because the circulatory system is a way for nutrients and other stuff to flow through to your muscles, brain and organs (The nutrients and stuff are like cars). The blood veins, and vessels are like the roads that direct the stuff to the places they need to be.

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.