What is a substance that provides the host immunity by introducing a weakene (attenuated) or killed (inactive) version of a virus?

Vaccines are the substance that provides immunity to the body by introducing a weak or dead virus.

Explanation:

Vaccines are not the medicines which helps in the prevention of disease in animals. Vaccine contains weak or dead microorganisms when injected in our body. Our body makes antibodies according to the structure of microbes which are injected. So whenever, the microbes enter into the body, our body is prepare for it. So the microbes cause no or less damage to the body.

"a scientist studying a whale and its surroundings would need to understand the structure of atoms in case something was negatively affecting the whale or its surroundings."

explanation:

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