Final answer:
Layer polymorphism (Option D) is the correct term for polymorphs differing by the stacking sequence of identical sheets. This concept influences the properties of substances and is seen in various domains, including crystallography and the structural study of proteins.
Step-by-step explanation:
Polymorphs that differ by the stacking sequence of identical sheets are known as Layer polymorphism (Option D). This type of polymorphism refers to the different possible arrangements of identical layers within a crystal, where the internal atomic arrangement and crystal structure vary despite having the same chemical composition. A classic example of layer polymorphism can be seen in graphite and diamond, which both consist of carbon atoms but have different stacking sequences that give rise to different physical properties.
The ß-pleated sheet conformation in proteins is another instance where sequence polymorphism plays a role in determining the protein's structure and function. The ß-pleated sheet is a secondary structure found in proteins, where regions of polypeptide chains align side by side. These aligned regions can either be parallel or antiparallel and are connected by hydrogen bonds, influencing the overall structure of the protein.
Understanding the concepts of polymorphism and stacking sequences is crucial in areas such as material science, crystallography, and molecular biology, where they contribute to the properties of substances at the molecular level.