The answer to your question is answer choice .1 Independent variable.
In ecology<span>, a </span>niche<span> (</span>CanE<span>, </span><span><span>UK:</span> <span>/<span>ˈniːʃ</span>/</span></span><span> or </span><span><span>US:</span> <span>/<span>ˈnɪtʃ</span>/</span></span>)[1] is the fit of a species living under specific environmental conditions.
<span>https://en.wikipedia.org/wiki/Ecological_niche</span>
If you are implying one these choices not needed for survival it would be parents only when you can survive on your own (I'm not that sure but I hope this helped the slightest but)
Answer:
50%
Explanation:
According to the given information, the allele for the red-green colorblindness is inherited in an X linked recessive manner. Let's assume that the allele X^c is responsible for red-green colorblindness. The woman is normal but had a colorblind father (X^cY). Fathers give their X chromosomes to the daughters while their Y chromosome is transmitted to their sons. The sons get their X chromosomes from the mother.
The colorblind father has transmitted the X-linked allele for the red-green colorblindness to his daughter. Therefore, the genotype of the woman is X^cX. The woman would produce two types of eggs: 50 % with X^C and 50% with X. Therefore, 50% of sons of this woman would get X linked allele for the red-green colorblindness and would be affected by the disorder while the rest 50% of her sons will be normal.