Answer:
Fatty acids are long chain carboxylic acids, they contain the carboxyl, COOH, functional group. The general formula for a fatty acid is R-COOH where R represents a long hydrocarbon chain. If the hydrocarbon chain, R, contains only single bonds between the carbon atoms, the fatty acid is said to be saturated.
It has the same origin as other connective tissues and it connects all the body systems together.
I am pretty sure that the answer is carbon dioxide.