The influential scientist known for her pioneering research on radioactivity is Marie Curie. She conducted groundbreaking work in the early 20th century, discovering the elements polonium and radium. Curie's research significantly advanced the understanding of radioactive materials and their applications, earning her two Nobel Prizes in Physics and Chemistry. Her work laid the foundations for modern nuclear physics and medicine. Additionally, Curie was a trailblazer for women in science, demonstrating that perseverance and intellect can transcend gender barriers in the scientific community.