Final answer:
Contraceptive foams, creams, and jellies should be inserted deep in the vagina near the cervix to be effective as they act as a barrier to prevent sperm from reaching an egg for fertilization.
Step-by-step explanation:
Contraceptive foams, creams, and jellies are forms of chemical barriers used in contraception to prevent sperm from reaching an egg for fertilization. These contraceptives must be applied deep in the vagina near the cervix to be effective. Placing them too close to the vaginal opening or in other incorrect locations will not provide the intended contraceptive effect. They work by creating a barrier at the cervix and killing sperm with spermicide.
When using these forms of contraception, it is crucial that the product is inserted properly. According to the options provided, they must be inserted as follows: 1) deep in the vagina near the cervix. This is because the cervix acts as the gateway to the uterus, and placing the contraceptive barrier near it helps prevent sperm from traveling into the uterus and reaching the fallopian tubes where fertilization usually takes place.