Look at the diagram. The function of part 1 is to provide an efficient _ supply. What one word completes the sentence?

The picture is cut off, but I believe the word is blood as 1 is pointing at some sort of blood vessel.

Explanation:

a axis of a graph is a color or shade so we can all go outside and have a party so we can eat   some grilled cheese sammiches and broccoli and have some ugly fun times

i don't know why i put this, i know its not the i was just bored : p

delete this answer while you can