Which of the following scientists is known for his theory of "survival of the fittest"?

The theory of "survival of the fittest" is most often associated with Charles Darwin, though the phrase itself was actually coined by philosopher Herbert Spencer. Darwin developed the concept of natural selection, which explains how species adapt and evolve over time, with those best suited to their environment more likely to survive and reproduce. This foundational theory significantly advanced our understanding of evolutionary biology.

Darwin's work, particularly in "On the Origin of Species," provided robust evidence of how organisms change through gradual modifications and how competition for resources leads to natural selection. His observations during his expedition and extensive studies of various species led him to articulate this theory, making him a seminal figure in the field of biology.

The other scientists listed contributed significantly to different areas in biology and genetics but do not specifically address the concept of "survival of the fittest" or natural selection in the manner that Darwin did. For instance, Cuvier is known for his work in paleontology, Lamarck proposed an earlier evolutionary theory, and Mendel is renowned for establishing the laws of inheritance, which focus on genetic traits rather than evolutionary processes.