Endothermic processes absorb heat energy from surroundings

Steps:

• Recall endothermic reactions absorb heat, increasing system energy (ΔH > 0).
• Evaluate A: Bond formation releases energy, exothermic.
• Evaluate B: Fuel cells produce electricity via oxidation, releasing energy.
• Evaluate C: Photosynthesis uses light energy to build glucose, absorbing heat.
• Confirm D: Combustion of methane releases heat, exothermic.

Why C is correct:

• Photosynthesis (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂) requires energy input from sunlight, making it endothermic by definition (ΔH positive).

Why the others are wrong:

• A: Atoms bonding to form molecules releases energy as bonds form, exothermic.
• B: Fuel cell reactions generate electrical energy from chemical energy, exothermic process.
• D: Methane combustion (CH₄ + 2O₂ → CO₂ + 2H₂O) produces heat, exothermic.

Final answer: C