In the 11th century, a Chinese scientist named Shen Kuo was one of the first people to develop a theory of Earth's changing land
scape. From a number of observations, he concluded that some cliffs and other landforms are formed by the processes of erosion and deposition. About 800 years later, an American scientist named William Morris Davis developed his theory of the cycle of erosion, in which he reasoned that flowing rivers form and shape many landforms. The example described above suggests that
A. people from different cultures and living at different times can contribute to scientific knowledge.
B. only people from Western Europe have developed useful scientific theories.
C. none of the scientific theories developed in the past have been accurate.
D. American scientists were the first to theorize that erosion can play a role in shaping land forms.
