Why do we resemble both parents but are identical to neither?

Why do children resemble their parents, but are identical to neither?

• Half a child's chromosomes have come from each parent. This means that:

1) Children get some of their alleles from each of their parents.

2) This is why most children look a bit like both of their parents.

3) But they won't be exactly like either one of their parents because they haven't got all the same alleles - some came from the other parent.

4) In fact, every child will have a new, unique combination of alleles - that's why no two people in the world are exactly the same (apart from identical twins).