Suppose a researcher studied the occurrence rates of a specific mental illness in monozygotic and dizygotic twins.She finds that if one twin suffers from the mental illness,the other twin is much more likely to also have the mental illness if the pair are monozygotic twins.What conclusion should the researcher draw from this evidence?
A)The incidence of this type of mental illness is strongly influenced by genetics.
B)The incidence of this type of mental illness is completely based on environmental factors.
C)Monozygotic twins are at an increased risk of developing mental illness.
D)Dizygotic twins are at an increased risk of developing mental illness.

Question

Quizplus · Accepted Answer

If one twin is more likely to have the illness when it is a monozygotic twin, it suggests that genetics plays a significant role in the incidence of the illness. This is because monozygotic twins share all their genes, while dizygotic twins on average only share half of their genes. If the illness were entirely based on environmental factors, then the occurrence rate in both types of twins would be the same.

Suppose a Researcher Studied the Occurrence Rates of a Specific