Because they are injecting you with a small dose of the disease. Just enough for your immune system to identify and build defenses against.
Inoculation- injecting someone with a small dose of a virus to help them build up defense to a disease.
Build defenses and train for combat.
dirt and earth
he was an engineer and he helped build forts and other defenses
Built walls and trained soldiers.
Vaccination entails giving the person a weakened form of the disease. This triggers the body's immune system to build up antibodies to the disease. Then if the real disease tries to attack the body, it is already ready to fight back.
Creatine is a chemical that provides energy to muscle and is taken to build up muscle. Injecting it into a mouse would probably add muscle and give it strength.
When combined with heavy weight training, ingesting protein and injecting testosterone, the tens unit will build massive bulk.
Fuel injection pump
By creating security "baselines"
he was an engineer who helped build forts and other defenses