The answer is Pennsylvanian. I worked on this before. The Pennsylvanian era is a subperiod of the Carboniferous Period. i really hope this helps :)
<span>Their progress and wealth is highly dependent on the harvests, and
the price of grain. They probably have to import some industrial
products and if they had a bad year (weather, other catastrophies, poor
technology) they can't get the necessary amount of industrial products
in exchange for their surplus e. g. in grain. </span>
The lowland river system.
When to talk about the plate tectonic it sound the same as our continents as we see in the ancient days you were having two continents which is laurasia and Gondwanaland
Answer: Scientists know that the Colorado River carved Grand Canyon. ... The age of the river falls between the rocks determined to be older than the river and those determined to be younger. Through this method, scientists have estimated an age for the river, and thus the canyon through which it flows, of 5-6 million years.
Explanation:
