Final answer:
The true statement about a pedigree chart is that it illustrates how an inherited disorder or disease is distributed in a family. It's a tool that helps determine the inheritance pattern of traits and likely carriers within a family lineage.
Step-by-step explanation:
The statement that is true of a pedigree chart is option (d) it illustrates how a single inherited disorder or disease is distributed in a family. Pedigrees are used to analyze patterns of inheritance, and through them, one can determine if a trait is sex-linked or autosomal. Each row in a pedigree chart represents a generation, with circles representing females and squares representing males. These charts do not predict the actual occurrence of a disease in an individual, but they help identify potential carriers and the likelihood of offspring inheriting a genetic disorder.