Is It possible for two parents with a round jaw to have a child with a square jaw? Why or Why not

Yeah it's possible. Even though both parents have round jaws... that may be the result of a dominant trait overpowering the recessive trait. As long as both parents have the recessive gene (in other words they're heterozygous traits) then there is a possibility for a child to be born with a square jaw.

if you know your abc's you should be able to get your answer or just use google