Final answer:
The intelligent design movement argues that life forms are too complex to have formed naturally and must have been created by a higher intelligence. However, the theory of evolution by natural selection provides a clear explanation for the development of life on Earth, although it does not explain life's earliest origins.
Step-by-step explanation:
The intelligent design movement asserts that life forms are too complex to have been formed by natural processes and must therefore have been created by a higher intelligence. However, the theory of evolution by natural selection provides a clear explanation for the development of Earth's remarkable variety of life-forms. While it does not directly solve the mystery of life's earliest beginnings, the hypothesis is that life will arise whenever conditions are appropriate. Intelligent design, on the other hand, is not a scientific explanation because it posits the existence of an unknown designer that cannot be measured or tested.