Why are Hershey and Chase credited with identifying DNA as the carrier of heredity even though DNA had been discovered many years before?

The correct answer will be - they proved that DNA is the heredity material of the organism.

Explanation:

The molecule present in the nucleus called nucleic acid-DNA was discovered by the Friedrich Miescher in the late 1860s.

This molecule was later thought as the genetic material of the organism which was proved by the experiments of the Hershey and Chase in 1952 around 90 years later after the discovery of the DNA. This solved the mystery of the heredity material as the scientists wanted to prove whether the genetic material is proteins or DNA.

Thus, they were credited for identifying the DNA as the genetic material.