The concept of "fixity of species" was a common belief based on a very limited understanding of:
the biblical principle "after its kind"
genetics
taxonomy
paleontology

Taxonomy

Explanation:

The concept of "fixity of species" was a common belief based on a very limited understanding of taxonomy.

A

Explanation:

"Fixity of Species" referred to the unchanging of nature and everlasting presence of life created during genesis. All other terms refer to key components of the formulation of evolutionary theory that are not in line with biblical thinking.

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)