Answer:
D. were widespread due to many low-lying land masses.
Explanation:
Cambrian Period was the first geological period of the Paleozoic Era, it occurred between two ice ages; Proterozoic and Ordovician. During these era, there were mass extinctions due to the decrease in global temperature.
Cambrian seas were widespread due to many low-lying land masses.
I think how long and how often.
The resulting erosion at the base of a waterfall can be very dramatic, and cause the waterfall to "recede." The area behind the waterfall is worn away, creating a hollow, cave-like structure called a "rock shelter." Eventually, the rocky ledge (called the outcropping) may tumble down, sending boulders into the stream
Answer:
A cultural hearth is the origin location of the cultural trait being spread through diffusion. Therefore, the role it plays in the diffusion of a cultural aspect is being the starting point. From that point on, it will either spread as hierarchical diffusion, stimulus diffusion, relocation diffusion, or expansion diffusion.