Molecular features in biology primarily involve studies of:

Molecular features in biology focus on the study of the molecular components that make up living organisms, specifically DNA, RNA, and proteins. Comparative genomics and DNA sequences play a crucial role in this field as they allow scientists to compare the genetic material of different species to understand evolutionary relationships, gene function, and the regulation of biological processes.

By analyzing DNA sequences, researchers can identify similarities and differences between organisms, leading to insights about genetic variation, evolutionary history, and the molecular basis of traits. This approach is fundamental in modern biology as it underlies many areas of research, including biotechnology, medicine, and conservation.

While the other choices mention important aspects of biology, they do not primarily focus on the molecular level. Understanding protein structures and physical characteristics can contribute to biology, but these are typically studied within the broader contexts rather than as the main focus of molecular biology itself. Ecological roles relate to how organisms interact with each other and their environment and, while vital, do not concentrate on molecular features.