When each offspring receives a sample half if the parents' genes, by chance some will get a good sample, some a poor sample, but most will get an average.
(each offspring; receives; a sample half) (some; will get; a good sample; T:When each offspring receives a sample half) (some; will get; an average; T:When each offspring receives a sample half; T:most)
each offspring some some
receives will get will get
a sample half
a good sample T:When each offspring receives a sample half
an average T:When each offspring receives a sample half T:most