Final answer:
Chargaff's research confirmed that the quantities of adenine and thymine, as well as guanine and cytosine, are equal in an organism's DNA. This fundamental rule is known as Chargaff's rules and contributed to the discovery of the DNA double helix structure by Watson and Crick.
Step-by-step explanation:
True, Erwin Chargaff's research indeed indicated that the amount of adenine (A) in an organism's DNA always equaled the amount of thymine (T), and the amount of cytosine (C) equaled the amount of guanine (G). This rule is known as Chargaff's rules and was confirmed by examining the content of DNA in various species. The concentrations of these nucleotide bases do not vary within a species but vary between different species. These findings were crucial in aiding Watson and Crick with their discovery of the DNA double helix structure.