Final answer:
The virus that infects and kills cells, leading to AIDS is the human immunodeficiency virus (HIV), which weakens the body's immune system by attacking helper T cells. This damage to the immune system can result in acquired immune deficiency syndrome (AIDS), where bacteria and viruses that don't normally cause disease can cause illness.
Step-by-step explanation:
The virus that infects and kills cells, thus weakening the body's immune system and leading to AIDS is the human immunodeficiency virus (HIV). HIV is a virus that attacks the immune system, specifically the helper T cells, and over time, it can cause acquired immune deficiency syndrome (AIDS). AIDS is a collection of symptoms and infections resulting from the damage to the immune system by HIV. When the immune system is weakened, bacteria and viruses that do not normally cause disease in healthy people can easily cause disease in an AIDS patient.