Final answer:
Condoms are the best barrier method to prevent the spread of certain STDs and unintended pregnancies.
Step-by-step explanation:
The best contraceptive method that involves a barrier to help prevent the spread of certain STDs is condoms. Condoms create a physical barrier between partners, preventing direct contact and reducing the risk of transmitting STDs such as HIV, gonorrhea, and chlamydia. They are also effective in preventing unintended pregnancies.
Learn more about contraceptives