Answer
Microbes were the focus of Waksman's soil research. He dedicated his career to studying the microorganisms that inhabit soil, recognizing their crucial role in nutrient cycling and soil health. His groundbreaking work led to the discovery of numerous antibiotics, including streptomycin, and established the field of soil microbiology. Waksman's research revolutionized our understanding of soil ecology and paved the way for advancements in agriculture and medicine.