IMAT 2018 Q25 [Phenotypes]

Which of the following could explain why the phenotype of a healthy female child may show
differences from her healthy biological brother (apart from the gender)?

  1. independent assortment after the formation of the female zygote
  2. crossing over between a chromosome from the sperm and a chromosome from the egg
  3. random alignment of homologous chromosomes at the equator of the cell during
    metaphase I.

A. 1 and 2 only
B. 1 only
C. 2 only
D. 2 and 3 only
E. 3 only