_ is transmitted through infected blood and hypodermic syringes.

Explanation

HIV (Human Immunodeficiency Virus) is primarily transmitted through several key routes. The most common mode of transmission is through unprotected sexual contact with an infected individual, where the virus can enter the body through mucous membranes. Additionally, sharing needles or syringes among intravenous drug users poses a significant risk, as it allows for direct blood-to-blood contact. HIV can also be transmitted from an infected mother to her child during childbirth or breastfeeding, highlighting the importance of preventive measures for pregnant women living with HIV. Lastly, although less common, transmission can occur through blood transfusions or organ transplants from an infected donor, particularly in areas where blood screening is inadequate. Understanding these transmission routes is crucial for implementing effective prevention strategies to reduce the spread of HIV.