Tay-sachs disease is a rare human disease that is inherited in an autosomal recessive fashion. a woman whose grandfather’s sister died in infancy of the disease is married to a man whose brother died of the disease. if they have children, what is the probability that their first child will have tay-sachs disease?

    a woman whose grandfather's sister had ts has a grandfather who had a 2/3 chance of being a carrier. she herself has 1/4 of that risk, or a 1/6th risk. her husband has a 2/3rds risk of being a carrier. if they're both carriers, the risk for anyone of their children of having the disorder is 1/4.

Immunization is the introduction of a foreign substance to provoke  the immune response system.  immunizations are the same as vaccinations. it introduces foreign (but dead/ weakened) illnesses to train the body to fight against them. specific viruses and bacteria have specific antigens, antigens act sort of like name tags. these name tags the immune system recognize what's dangerous to the body and what's safe.