Final answer:
Fundamentalist Christians led by William Jennings Bryan rejected Darwinian evolution due to its contradiction of the biblical account of creation. However, it is important to note that most major denominations in the United States accept the compatibility of evolution with their theological beliefs.
Step-by-step explanation:
The statement that is NOT true regarding the disagreement with evolutionary theory by Fundamentalist Christians led by William Jennings Bryan is that most Americans believed in both evolution and creationism.
In the 1920s, many standard textbooks contained information about Darwin's theory of evolution, which the Fundamentalist Protestants targeted as representative of all that was wrong with urban society. They believed that the teaching of evolution and the secular nature of public education threatened the values of rural America.
However, it is important to note that most of the major denominations in the United States have statements supporting the acceptance of evidence for evolution as compatible with their theologies.