Question

how do barrier devices differ from hormonal methods for contraception?
barrier devices are placed on the skin, while hormonal methods are inserted inside the uterus for varying periods of time
barrier devices help prevent pregnancy, while hormonal methods help prevent sexually transmitted diseases (stds)
barrier devices release chemicals into the body, while hormonal methods use physical obstacles.
barrier devices block sperm from reaching an egg, while hormonal methods prevent ovulation

Explanation:

Barrier devices (e.g., condoms, diaphragms) create a physical blockage. Hormonal methods (e.g., birth control pills) work by inhibiting ovulation. Option A is incorrect as hormonal methods aren't just inserted in the uterus (e.g., pills are oral). Option B is wrong because barrier methods can help prevent STDs (hormonal methods don't). Option C has it reversed - barrier devices use physical obstacles, hormonal methods release hormones (chemicals).

Answer:

D. Barrier devices block sperm from reaching an egg, while hormonal methods prevent ovulation.