Tom with type ab blood marries anna. they have two children: eric with type b blood and jessica with type a blood. anna’s father paul has type o blood, and her mother elizabeth has type a blood.

Do you know what blood type you are? If you don't, you're not alone. Although blood type is a fundamental part of our biological make-up, determined by our genes - like having blue eyes or being left-handed - unless you pay for a private test, there are only three ways to find out which you are.

The first is to be so unwell you need a blood transfusion. The second is to be pregnant - women are screened to prevent a rare complication when their blood type differs from the baby, creating antibodies that may interfere with subsequent pregnancies. Or you could give blood and your type will be on your donor card.
So, what i'm saying is your answer is ABO Blood type

~Tomas

it would lead to upper respiratory infections and pneumonia.