Bibliography (5):

1. A Novel Human Sex Difference: Male Sclera Are Redder and Yellower than Female Sclera

2. Cultural Evolution in Animals

3. The relationship between baseline pupil size and intelligence

4. Wikipedia Bibliography:

   1. https://en.wikipedia.org/wiki/Sclera  :

      https://en.wikipedia.org/wiki/Sclera

   2. https://en.wikipedia.org/wiki/Iris_(anatomy)  :

      https://en.wikipedia.org/wiki/Iris_(anatomy)