Imagine a car as a model that represents the human body , with its parts performing various functions similar to human body systems which two statements are correct analogies

The propositions are:
A. The gas in the car is the digestive system that provides the necessary energy.
B. The frame of the car is the digestive system that provides structure and support to the body.
C. The exhaust system of the car is the excretory system that removes waste. 
D. The engine of the car is the digestive system that circulates nutrients to the rest of the body.
E. The oil in the car is the excretory system that protects and coats the body.

The right answer is: C and D
*The exhaust system in the car removes waste from the engine like carbon dioxide, carbon monoxide, and several oxidated particles that are unuseful. The same thing for the excretory system in human, it excretes urea, creatinine, and urobillongen (all are wastes from a metabolism).
*The nutrient in the car are represented by the fuel, it is the component that gives energy to the wheels to roll.