In which age group is the risk of $STDs$ highest?

All reproductive tract infections $(RTIs)$ are $STDs$,but all $STDs$ are not $RTIs$. Justify with an example.

Syphilis is an infectious bacterial disease caused by $Treponema\ pallidum$ with $3$ stages:
$(A)$ Infectious painless ulcers on the genitals $\quad(i)$ First
$(B)$ Blindness, heart trouble, aortic impairment $\quad(ii)$ Second
$(C)$ Skin lesions, hair loss, swollen joints $\quad(iii)$ Third
Which of the following is the correct match between the symptoms and stage?

Which of the following can be complications resulting from $STDs$ without timely detection and treatment?
$A.$ Pelvic inflammatory disease $(PID)$
$B.$ Stillbirths
$C.$ Infertility or even cancer of the reproductive tract
$D.$ Ectopic pregnancies

The sexually transmitted disease that can affect both the male and the female genitals and may damage the eyes of babies born of infected mothers is

$STDs$ caused by viruses are:
$I. \;AIDS$
$II. \;Hepatitis-B$
$III. \;Genital herpes$