C- The water was a constant shallow sea during that time.
This was happened to the Grand Canyon area during the Permian Age.
<u>Explanation:</u>
The Grand canyon consists of the most studied sequence and complete rock on earth. They are nearly 200 million to 2 billion of years old, of which most of them were deposited in shallow, warm seas and near the ancient and the sea shores which were long gone.
The youngest formation of rock in the grand canyon is the Kaibab Limestone, which was laid down during the Permian age by the advancing warm and shallow sea. Although, the areas climate has been changing constantly during recent times from cool and wet pluvial to semi arid conditions. And also, with less water to cut, the erosion has also reduced greatly.
You didn't add the choices, but I've had this question before the answer is that nearly all of the male immigrants were male, so children came from unions with Native Americans.
