There are 4 valence electrons in an atom of carbon. Carbon is in group 4A of the periodic table. There are 6 electrons in a carbon atom but only 4 of them are valence. carbon can never form more than 4 bonds and is unhappy with less than 4.
Well this really depends on if the father is homozygous or heterozygous for type A.
But lets say he is homozygous for right now. That mean if he were to produce offspring with a type O women then all of there offspring would be heterozygous for type A.
If the father was heterozygous for type A and he produced with the same type O mother then the offspring would be either type O or heterozygous type A. In this case there is a 50% chance either way.
Hope this makes sense(;
For this you are going to use S as the dominate and r for the recessive. Since both of the parents are squared eye the offspring's likely chance of having round eyes will be 0%.
An example i can think of is...
the amount of salt present in human cells cytoplasm suggests we evolved from species in the sea