Final answer:
Proteins can have separate domains with distinct structures and functions, which is a true statement. Domains are stable parts of proteins that often fold independently and are indicative of protein functions. They also play a role in evolution and genetic diversity.
Step-by-step explanation:
Proteins can indeed have separate domains with distinct structures and functions. This statement is true. A structural domain is a part of a protein that folds independently and is stable on its own. These domains can appear across different proteins and are often indicative of the function of the protein. For instance, the Pleckstrin Homology (PH) domain allows proteins to participate in cell-signaling pathways. Domains are evolutionary units and may be shared between proteins that belong to gene families or superfamilies. The diversity in structural domains is a result of both natural genetic events and can be further expanded by genetic engineering to create chimeric proteins with novel functions.