Why do teens have the highest hiv infection rate​

They dont South Africa has the highest number of people living with HIV in the world (7.5 million).

Explanation: "The risk for HIV for most youth begins when they start having sex or injecting drugs. (A small number of children are born with HIV.) For both males and females, having sex under the influence of drugs or alcohol can increase risky behaviors that could lead to becoming infected with HIV."

since you have not provided the options here i   am going to give you general overview about hormone.hormone are actually the part of endocrine system in our body and produced by the endocrine glands. the hormones act like a chemical messenger   within human body. once produce by the glands they   travel through the blood stream and reach at specific or target tissue and organs   which result in control of our body function. the hormones are specific in their work and work on only the targeted tissue or organ   . with the of hormone endocrine system regulate the heart rate , metabolism, our mood and   growth as well as the development and even the sleeping cycle etc. they actually are the messenger for body cell and organs .