Without considering the variation provided by crossing-over, how much will two siblings from one set of parents vary from each other?
a. There is one chance in 23 of getting identical sets of chromosomes from one parent, times two because there are two parents; therefore, two siblings out of 46 will be identical except for the extent of crossing-over.
b. Siblings inherit essentially 50% of their genes from each parent, but two sibling offspring may share with each other from zero to 23 chromosomes in common from each parent and therefore vary widely from each other.
c. All siblings from the same parents are identical to each other and demonstrate traits that are exactly halfway between their parents' traits.
d. Siblings receive 100% of one parent's genes or the other parent's genes so they will either be identical if they receive the same parent's genes, or nothing alike if they receive different parent's genes.
e. Siblings inherit copies of the same 23 pairs of chromosomes from each parent and only crossing-over provides any differences between siblings.