What is the field of genetics primarily concerned with?

Genetics is fundamentally the study of inheritance—specifically, how traits and characteristics are passed from one generation to the next through genes. This field explores the mechanisms of heredity, including how genes are structured, how they function, and how variations arise within a population over time. It also encompasses the understanding of genetic variation and how this variation contributes to the diversity of traits observed in organisms. This includes both classical genetics, which involves the study of Mendelian inheritance, as well as modern genetics, which explores molecular genetics and the role of DNA.

The other fields mentioned, such as environmental effects on organisms, cellular structures, and human behavior, while important in biology, do not directly address the inheritance of traits, which is the essence of genetics. By focusing on genes, heredity, and the transmission of traits through generations, genetics plays a crucial role in understanding biological diversity and the relationships between different organisms.