Once a sensitive period passes a. learning cannot occur b. learning can occur but is less efficient c. a fetus is unaffected by teratogens d. a fetus is more likely to be affected by 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