What fundamental difference dictates the geographic split between Eastern and Western tree frog survival strategies?

Answer

The deep-water dependency of the East contrasts with the drought tolerance and rocky-crevice reliance of the West

The climate dictates amphibian survival; Eastern species rely on sustained high moisture, while Western species exhibit adaptations for drier conditions tied to specific geological features.

What fundamental difference dictates the geographic split between Eastern and Western tree frog survival strategies?
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