It’s C. I just recall hearing my teacher say that... sorry I have no explanation
Sister chromatids have different alleles although carry same genes on same loci. So if it doesn't happen so, like if there are same alleles on sister chromatids then there is a problem in its formation. i.e., male and female alleles haven't contributed equally ( may be an error during their segregation process ). And obviously it doesn't happen in a real cell so we must understand this point. Because normally whenever it happens there's one half from the male and one half from the female. (i.e. maternal and paternal alleles contribute equally).
I hope you get the answer!!!
He observed 15 different finch species that originated as one ancestral bird. all differing in body shape, beak size, and mating habbits
A grow and divide uncontrollably.
