Answer:
A. Cambrian explosion , Active plate margin, True.
Step-by-step explanation:
- The burgess shale is a window into life on earth during the exposition of Canadian Rockies. Itis one of the earlier imprints containing the soft part imprints.
- Fossil deposits of burgess shale correlate to the Stephen formation. that were collected about 508 million years ago. Beds were deposited at the base of the cliffs 160 meters tall.
- North American plate is considered as an active plate margin, as this margin is moving westwards. And the pacific plate is shrinking in size. The presence of Icelandic Arcand festoons depicts this.
- The laptus ocean in the paleozoic era was an Icelandic volcano found in the ancient oceanic crust of ophiolites of Newfoundland. This ocean was earlier also named as the titan impetus.