How is $AIDS$ transmitted?

The World Health Organization has started a number of programmes to prevent the spreading of $HIV$ infection.
Few such steps include:
$I.$ Ensuring the use of disposable needles and syringes.
$II.$ Free distribution of condoms.
$III.$ Advocating safe sex.
$IV.$ Controlling drug abuse.
Which of the steps given above are correct?

Which of the following viruses contains the enzyme reverse transcriptase?

Provide the full forms of the following abbreviations:
$(i)$ $DNA$
$(ii)$ $AIDS$

In an $HIV$ infected person,the $HIV$ produced in macrophages enters which cells to replicate and produce its progeny?

Which of the following effects is observed in an individual infected with $HIV$?