All of the above. Good luck with the bio
All their children will have heterozygous genes because squidward is "purebred", or homozygous dominant. His wife has to be homozygous recessive for a recessive trait to show up. Every time you cross a homozygous dominant trait with a homozygous recessive trait, you will get heterozygous kids. This means all of them will have light blue skin.
