Answer
d. a lower ratio of oxygen to hydrogen.
Work Step by Step
A lipid has a lower ratio of oxygen to hydrogen compared to a carbohydrate.
A carbohydrate's basic formula is $(CH_{2}O)_{n}$. For every 1 oxygen atom, a carbohydrate has 2 hydrogen atoms.
In comparison, lipids are characterized by a high hydrogen to oxygen ratio. A fat called tristearin has the formula $C_{57}H_{110}O_{6}$, which is more than 18 hydrogen atoms per 1 oxygen atom.
