A scientist investigated the effect of a directional light stimulus on the distribution of IAA in seedlings - AQA - A-Level Biology - Question 6 - 2021 - Paper 1

In fruit flies, males have the sex chromosomes XY and the females have XX. The allele for eye color is carried on the X chromosome. The allele for red eyes, R, is dominant to the allele for white eyes, r. Therefore, males are more likely to have white eyes because they only have one X chromosome. If a female is homozygous for red eyes (XXRR), all offspring will inherit an X from the mother carrying the red eye allele, while the male offspring can only inherit one X from the mother which can carry either a red-eye or white-eye allele.