(the oldest and simplest of these fossiles) in the International System of Units. Other question of my interest are the same estimations of volume an weight for alive animals with bilateral symmetry. I apologize if my question bother some user of the site, I'm not a biologist. Many thanks, I wait your response.

There is a typo in my second question: I'm interested in the same estimations of volume an weight for alive animals that have not bilateral symmetry.

I was motivated and inspired to ask these questions in a book by Walter Álvarez and a graphic that refers in a book John D. Barrow.

With the word "weight" I want to understand mass expressed in the cited SI.