Passive immunity lasts only as long as the antibodies survive in body fluids.
Immunization can be active or passive.
Immunization can put antibodies in body fluids.
what can put antibodies in body fluids?

[1] Chemical energy
[2] animals
[3] death
[4] humans
[5] h2o
[6] immunization
[7] mammals
[8] collagen injections