Final answer:
Unprotected sex with an infected partner, recent blood transfusions, and sharing needles are all activities that can increase the risk of contracting hepatitis B. The virus is spread through contact with infected blood and other body fluids.
Step-by-step explanation:
The activities that can increase the risk of contracting hepatitis B are all of the options listed: unprotected sex with anyone who has hepatitis B, recent blood transfusions, and sharing needles with anyone. Hepatitis B (HBV) is transmitted through contact with infectious blood or body fluids such as semen or saliva. High-risk behaviors for HBV infection include intravenous drug use and having sexual contacts with an infected individual. Health-care workers are also at risk from needle sticks and other injuries when treating infected patients. In addition to using protective equipment like gloves and face protection, health-care settings can reduce transmission by strictly adhering to protocols for disinfecting and sterilizing equipment and by offering HBV vaccination to all workers at risk.