Fact 1: Plants use unsaturated fatty acids to store energy. Fact 2: Sunlight is turned into energy by plants. Given the two facts above, what do plants use unsaturated fatty acids for?

Pick your answer from: [I] Healthy heart. [II] Storing sunlight. [III] Storing moonlight. [IV] To keep their body heat.. [V] survival. [VI] Storing kibble. [VII] recycling. [VIII] staying warm.
The answer is:
[II]