As understood by modern geologists, the principle of uniformitarianism implies that Group of answer choices A. the Earth has always had the same basic appearance that it has today. B. igneous, metamorphic, and sedimentary rocks are uniformly mixed throughout the crust. C. physical processes observed today (such as erosion and volcanic eruptions) have been active in the past at approximately the same rates. D. physical processes observed today (such as erosion and volcanic eruption) occurred much more rapidly in the past, quickly sculpting the Earth's surface.

D. physical processes observed today (such as erosion and volcanic eruption) occurred much more rapidly in the past, quickly sculpting the Earth's surface.

Explanation:

physical processes observed today (such as erosion and volcanic eruption) have been active in the past and are responsible for the geologic history we see preserved in the rock record.

Uniformitarianism, in geology, the doctrine suggesting that Earth's geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change.

The Principle of Uniformitarianism states that the laws of nature that are in effect today, have been in effect forever. The major folds and unconformities seen in rocks could not have been produced in such a short time if the principle of uniformitarianism is applied.