It is possible to have a child with O blood despite the parents having different blood types.
While the man tested for B blood, he could have been a combination between type o and B whereas, the woman was a combination of type A and o. Since A/B are dominant, they would 'stand out' contrarily to o.
This means that their children could have AB or O blood.
This is possible, the rest of their family tree might have blood type O and it might have been past down in the generations to them and the sperm had blood type O
The fact that only cells are able to produce more cells is part of cell theory. The idea that organisms can develop independently of cells is called spontaneous generation, and it isn't supported by cell theory. Spontaneous generation suggests that living organisms develop from non-living matter.
