DNA and its structure was not isolated and understood until the mid 1900s. It serves as

The correct answer is letter d. the mechanism by which the "inheritance of acquired characteristics" operates.

a. the mechanism through which population evolution operatesb. an example of how the blacksmiths arms grow as large as they do. c. the mechanism by which the "strong principle of inheritance" operates. d. the mechanism by which the "inheritance of acquired characteristics" operates