Active immunity is generated by ____.

A) avoiding the disease
B) receiving a vaccination against the disease
C) receiving antibodies by injection
D) receiving memory B cells from a donor
E) receiving a booster vaccination

Active immunity is generated by the body's immune response to an antigen, either through natural exposure to the antigen (such as contracting a disease) or through vaccination. Vaccines contain weakened or inactivated forms of the disease-causing agent, which stimulate the immune system to produce antibodies and memory cells against the agent without causing illness. This results in long-lasting immunity against the disease.