Questions: Darwin's theory of evolution is also known as descent with modification through variation and natural selection; inheritance of characteristics acquired through behavioral changes in the parents; increased survival and reproduction of adaptive traits due to uniformitarianism; the appearance of life forms with new adaptations that are fixed and static.

The answer is the first one: descent with modification through variation and natural selection.

Explanation for each option:

• Descent with modification through variation and natural selection: This is the correct description of Darwin's theory of evolution. It emphasizes that species change over time, with variations occurring in each generation. Natural selection acts on these variations, leading to the adaptation of species to their environments.

• Inheritance of characteristics acquired through behavioral changes in the parents: This describes Lamarck's theory of evolution, not Darwin's. Lamarck proposed that traits acquired during an organism's lifetime could be passed on to its offspring, which is not supported by Darwin's theory.

• Increased survival and reproduction of adaptive traits due to uniformitarianism: While natural selection does involve the increased survival and reproduction of adaptive traits, uniformitarianism is a geological principle that suggests that the same natural laws and processes that operate in the universe now have always operated in the universe in the past. It is not directly related to Darwin's theory of evolution.

• The appearance of life forms with new adaptations that are fixed and static: This is incorrect because Darwin's theory emphasizes that adaptations are not fixed and static; rather, they are subject to change over time through the process of natural selection.

In summary, Darwin's theory of evolution is best described as "descent with modification through variation and natural selection."