Final answer:
The daily release of hot water into the pond from a local factory would most affect the health of fish in a local pond.
Step-by-step explanation:
Out of the given options, the factor that would most affect the health of fish in a local pond is D. The daily release of hot water into the pond from a local factory. Hot water can have several negative impacts on fish, including reducing their oxygen levels, disrupting their metabolism, and causing thermal stress. These factors can lead to decreased fish populations and overall poor health of the ecosystem.