Answer :
Final answer:
The decline was caused by non-native fish, fungus, and pesticides.
Explanation:
Factors that caused the rapid decline of the Sierra Nevada yellow-legged frog population include non-native fish introduction, fungus spread, and the potential impact of pesticides. The spread of Batrachochytrium dendrobatidis fungus, the introduction of non-native fish like North American bullfrog, and the presence of pesticides have contributed to the population decrease of the frog species.
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