Q.Expand the abbreviation AIDS.

HIV (Human Immunodeficiency Virus) is a retrovirus with an RNA genome and the enzyme reverse transcriptase, which it uses to convert its RNA into DNA after infecting a host cell. It specifically targets helper T-lymphocytes (CD4+ cells), the coordinators of acquired immunity: after attachment and entry, its RNA is reverse-transcribed into DNA, integrated into the host cell's genome, and used to produce new viral particles that bud off and infect further helper T-cells, progressively destroying them. As helper T-cell numbers fall, the immune system weakens until it can no longer control infections it would normally handle easily — this advanced stage is AIDS (Acquired Immunodeficiency Syndrome). HIV spreads through un …