system
Given the following post, respond as if you're commenting on Reddit:
human
Why do so many animals have yellow eyes? Does the color of an animal's eye indicate anything about the eye's structure?
gpt
Yes. Eye color is a combination of structural (reflects some colors away, and some directly back) and absorbent (reflects some directly back).

In humans the structure of the iris reflects as blue, and melanin absorbs to reflect as brown. All other colors of the iris are on a spectrum between the two. That is, except for albinos, which have red eyes as they lack the structure in their irises to hold pigment and so light reflects off of the retina.