Who proposed the theory of evolution by natural selection?

The theory of evolution by natural selection was proposed by Charles Darwin, making it the correct response in this context. Darwin articulated this theory in his seminal work, "On the Origin of Species," published in 1859. The central idea of his theory is that species evolve over time through a process where individuals with advantageous traits are more likely to survive and reproduce, passing those traits on to future generations. This concept transformed our understanding of biology and the diversity of life on Earth.

The other individuals mentioned made significant contributions to their respective fields, but their work did not involve the theory of evolution. Albert Einstein is renowned for his theories in physics, especially relativity, while Isaac Newton is best known for his laws of motion and universal gravitation. Galileo Galilei is noted for his contributions to astronomy, physics, and scientific methodology but did not address evolution in the manner that Darwin did. Therefore, the connection between Darwin and the theory of natural selection is foundational to modern evolutionary biology.