Historically, Poland has been part of the barrier against the steppe invassions, first the Mongols, then the Russians themselves. From that point of view, it would be central Europe, as the steppe peoples would be eastern Europe. Poles often lived within the HRE, which would place them squarely in the Mittel-europa.
The Cambrian Explosion refers to the metaphorical explosion of life that began 542 million years ago and lasted for roughly 40 million years. This lesson will cover the events that occurred during this time period.
How did the Cambrian explosion of life change the nature of the living world? Numerous filter/deposit feeders and large, mobile predators complicated the world food web, many defensive structures and behaviors were favored in natural selection due to propogating carnivores