Avery and his colleagues extract material from a killed sample of lethal bacteria. They eliminated carbohydrates, proteins, fats, RNA, and DNA from the extract and showed that exposure to the DNA alone could make non-lethal bacteria become deadly. What does this observation demonstrate about DNA

That the DNA is a transforming molecule

Explanation:

DNA molecule could make non-lethal bacteria become deadly and as such, it is said to be the molecule responsible for transformation.

The observation effectively demonstrated that DNA is the molecule that is responsible for inheritance of traits from one generation to another.

The DNA contains information about traits and these information are some ways passed on from one generation to another in a process known as gene expression.