Question

natural active immunity
artificial active immunity
natural passive immunity
artificial passive immunity
an antibody is injected into a person who has been bitten by a snake. the antibody infers resistance.
a person develops resistance to a virus picked up from a drinking fountain
a baby acquires resistance to a virus through antibodies obtained through breast milk.
a person is given an attenuated smallpox virus and develops resistance.

Explanation:

Step1: Analyze Natural Active Immunity

Natural active immunity occurs when a person's immune system responds to a natural infection. The scenario "A person develops resistance to a virus picked up from a drinking fountain" fits as it's a natural exposure (from the environment) leading to immunity. So match this to Natural active immunity.

Step2: Analyze Artificial Active Immunity

Artificial active immunity is from a vaccine (attenuated or inactivated pathogen). "A person is given an attenuated smallpox virus and develops resistance" is a vaccine - induced response, so match to Artificial active immunity.

Step3: Analyze Natural Passive Immunity

Natural passive immunity is when antibodies are acquired naturally, like from mother to child. "A baby acquires resistance to a virus through antibodies obtained through breast milk" is natural transfer (breast milk) of antibodies, so match to Natural passive immunity.

Step4: Analyze Artificial Passive Immunity

Artificial passive immunity is when antibodies are injected (not from natural infection or mother - child). "An antibody is injected into a person who has been bitten by a snake. The antibody infers resistance" is injection of antibodies, so match to Artificial passive immunity.

Answer:

• Natural active immunity: A person develops resistance to a virus picked up from a drinking fountain.
• Artificial active immunity: A person is given an attenuated smallpox virus and develops resistance.
• Natural passive immunity: A baby acquires resistance to a virus through antibodies obtained through breast milk.
• Artificial passive immunity: An antibody is injected into a person who has been bitten by a snake. The antibody infers resistance.