青蛙的绿色主要源于它们的皮肤色素和结构。青蛙皮肤中含有黄色素（xanthophores）和蓝色结构色（iridophores），这两种颜色混合后形成了绿色。此外，青蛙的绿色还具有重要的保护作用，可以帮助它们在自然环境中进行伪装，躲避天敌。绿色与周围植被的颜色相似，使青蛙更容易融入环境，从而提高生存几率。

English Explanation:

Frogs are green primarily due to the pigments¹ and structural² colors in their skin. Their skin contains xanthophores (yellow pigments) and iridophores (blue structural colors), which combine to create the green appearance. Additionally, the green color serves an important protective function, helping³ frogs camouflage⁴ in their natural environment. This allows them to blend in with vegetation, making it harder for predators⁵ to spot them and increasing their chances of survival.

青蛙的绿色是进化的结果，既是为了适应环境，也是为了生存。

The green color of frogs is a result of evolution, serving both environmental adaptation and survival purposes.