Drugs, chemicals, and radiation that can cause birth defects are known as
a. carcinogens.
b. progestins.
c. toxoplasmosis.
d. teratogens.

Which of the following accounts for someone who has had regular herpesvirus-mediated cold sore or genital sore flare-ups? a) re-infection by a closely related herpesvirus of a different strainb) re-infection by the same herpesvirus strainc) copies of the herpesvirus genome permanently maintained in host nucleid) copies of the herpesvirus genome permanently maintained in host cell cytoplasm