A rubber ball about to fall off a hill
Examples:
Respiratory System, (I think) Organ System, Circulatory System, Nervous System, etc.
Answer:
1. Abstain, Be faithful, or, as a last resort, use a Condom. Within a few years, Uganda had developed what researchers call a "social vaccine" against HIV: cultural norms about sexual responsibility, preached in clinics and public schools, as well as churches and mosques.
3.When used correctly every time you have sex, condoms are the best way to prevent sexually transmitted infections such as HIV. They have a very low failure rate and are effective for all forms of sex.
Fish are aquatic vertebrates with gills, appendages, if present, in the form of fins, and usually a skin with scales of dermal origin. They are the most ancient and most diverse of clad vertebrata
