Question

to abstain from any sexual activity and is the only one hundred percent effective method for preventing pregnancy and stds. withdrawal family planning abstinence rhythm

Explanation:

Abstinence means refraining from sexual activity. Withdrawal (pull - out method) has a high failure rate for preventing pregnancy and no protection against STDs. Family planning (like using contraceptives) and rhythm method (tracking menstrual cycle) also have limitations in full - proof prevention of pregnancy and no protection against STDs. Only abstinence completely stops the risk of pregnancy (as no sperm - egg interaction) and STDs (as no sexual contact for pathogen transmission).

Answer:

Abstinence