Answer: potential energy
Explanation:
The correct matching of the forms of energy with their respective sources is as follows:
- The energy associated with a gradient of ions across a membrane: potential energy
- The motion of individual molecules: kinetic energy
- The heat released from a living organism: kinetic energy
- The energy related to the height of a bird above the ground: potential energy
- The covalent bonds of a sugar molecule: potential energy
Therefore, the correct answer is:
- The energy associated with a gradient of ions across a membrane: potential energy