Question

Sponges and cnidarians are among the fossilized animals found in both the Ediacara Hills and the Burgess Shale from the Rocky Mountains of British Colombia. This observation requires that

A. North America and Australia were united to each other about 550 million years ago (mya).
B. only sponges and cnidarians existed at the time the sediments were deposited
C. ancestral sponges and cnidarians had formerly been terrestrial animals.
D. land that now comprises the Ediacara Hills and the Rocky Mountains was underwater about 550 million years ago.

Answer 1

The observation that sponges and cnidarians are found in both the Ediacara Hills and the Burgess Shale suggests that the land that now comprises these areas was underwater about 550 million years ago.

Step-by-step explanation:

The observation that sponges and cnidarians are found in both the Ediacara Hills and the Burgess Shale suggests that the land that now comprises these areas was underwater about 550 million years ago (option D). The presence of these fossils does not necessarily mean that North America and Australia were united (option A). It also does not imply that only sponges and cnidarians existed at the time (option B), or that ancestral sponges and cnidarians were terrestrial animals (option C).