James D. Watson is a renowned scientist who, along with Francis Crick and Maurice Wilkins, won the Nobel Prize in Physiology or Medicine in 1962. They won this award for their breakthrough work in the field of life science - Genetics. They are specifically known for their discovery of the double helix structure of DNA.

Option 1, Metallurgy, is not correct. Metallurgy pertains to study of metals their properties, production, and purification. Watson`s work revolves around biological sciences, not metallurgical sciences.

Option 2, Meteorology, is the study of atmospheric phenomena, specifically weather. Watson did not contribute in this field.

Option 3, Environmental protection, is a broad discipline focused on safeguarding natural resources and ecosystems, which also does not connect with Watson`s work.

Option 4, Genetics, is the correct answer. Genetics studies how traits are passed from parents to offspring and Watson, alongside his colleagues, made groundbreaking contributions to this field.