They are heridity hope this helps :)
Well , run off water plays a big part in this.
run off water is usually when water is in a puddle or on the ground and ran off into the sewer.
i hope this helps you a lot
No their babies won't look alike.
<h3>Explanation:</h3>
Both the couples mentioned here i.e. Sally - Harry and Emily - Ken are both identical twins. So they have similar pairs of genetic setup. This was possible because they developed from same zygote.
But during gametogenesis, crossing over and independent assortment occurs which brings about variation in genetic setup among the offspring. And it's very less probable that same crossing over will occur between the gametes of these couples. So, their offsprings won't look same.