Relate structure to function Assignment

[floppy]

Hi people, I'm new here.

I was asked to do this assignment where I relate the structure to the function. I did the assignment as best I could but it seems all I did was talk about which structure does which function.

I was asked to relate the structure to function of the following body systems:

Circulatory ststem
Digestive System
Nervous System
and Respiratory system

Can someone help me to RELATE the structure to function for theses systems please?