A probability problem (genetics), not homework, honest. 3 of 5 siblings are affected by an unknown inherited disease*. That this outcome is higher than 1 in 4 which is typically the case in recessive traits suggests that the disease is more likely to be dominant than recessive. Given 3 of 5 siblings are affected how much more likely is it that this genetic illness is dominant rather than recessive ?. Like I said this isn't homework so I can't confirm if any answer given is correct. [ *adult onset : inheriting the trait would not make their birth less likely ].