Answer:
Sunlight
Step-by-step explanation:
Abiotic means not alive, and the insects and fish options are alive, so we can eliminate those. Sunlight and rocks are left. Of these, the rock would not affect the water lilies, not as much as sunlight at least. Without sunlight, the water lilies would not be able to grow and thrive as all plants/flowers have sunlight as one of their basic needs, so sunlight must be the answer.