Final answer:
The birth control device that acts as a barrier to semen and microorganisms causing STIs is the latex condom. Condoms are the only contraceptive method that also prevents STIs, making them critical for safe sexual practices. Option a.
Step-by-step explanation:
The birth control device that provides a barrier to semen and microorganisms that cause STIs is A. latex condom. Condoms are a type of barrier method of contraception, which not only prevent sperm from entering the uterus and thus preventing pregnancy, but also protect against the transmission of sexually transmitted infections (STIs).
For maximum effectiveness and STI prevention, it is important to use condoms correctly, as they can sometimes break or be used incorrectly, leading to a failure rate with typical use. Of all birth control methods, only condoms can also prevent the spread of STIs, making them a unique and significant choice for safe sexual practices. The birth control device that provides a barrier to semen and microorganisms that cause STIs is the latex condom.