A study of breast cancer in a large sample of female twins found the following results.

Type of twin

Identical or monozygotic

(have identical inherited genes)

Fraternal or dizygotic (only about half

their inherited genes are the same)

For twins where at least one twin had breast cancer,

% where the other twin

% where both twins

had breast cancer

did not have breast cancer

80%

20%

12%

88%

7. Based on these data, which of the following statements is true? (5 pts)

Explain your logical reasoning for each statement.

a. Inherited genes are the main cause of breast cancer.

b. Inherited genes contribute to the risk of breast cancer, but they are not the main cause.

c. Inherited genes have no effect on the risk of breast cancer.