a:  veins ~
b:  part of a two way street
What:  
The blood pumping through the human body, and many other animals, can be thought of as a two way street with road separated by a wide distance. Blood goes out from the heart on one road and returns on another.
Useful?
Writer:  Lucrezia
LCC: 
Where: Reference Link Has Evaporated
Date:   Jul 25 2015  4:04 PM
# 8022 Critique Analogy
