Pre AP Biology -CELLS 1.4 Cellular Energy Requirements- MCQ Exam Style Questions -New Syllabus 2025-2026

The correct option is a.
Organic molecules like hydrocarbons are excellent fuels because they contain many $\text{C—H}$ bonds.
These bonds store a significant amount of potential energy due to the equal sharing of electrons.
During combustion, these high-energy electrons are transferred to oxygen, a highly electronegative atom.
This process releases energy as the electrons move to a lower energy state in $\text{H}_2\text{O}$ and $\text{CO}_2$.
An abundance of oxygen (option c) actually reduces the fuel value because the carbon is already partially oxidized.
Therefore, the high density of non-polar covalent bonds is the key factor for energy storage.