Answer:
Trichomoniasis
Explanation:
Trichomoniasis is an sexually transmitted disease that affects around 30% of world population. The common symptoms are frequent urge to urinate, vaginal bleeding, burning sensation during urination.
The causative agent of trichomoniasis is a protozoa called <em>Trichomonas vaginalis</em>. This protozoan can be transfer through the genital contact. The protozoa can easily be transfer from affected individual to the healthy individual.
Thus, the correct answer is option (3).
I would say zygote ® fetus ® embryo ® blastocyst
