please I'm interested in an estimate for the volume and weight, the mass, of (most) ancestral multicellular organisms. Wikipedia has the article Multicellular organism, and my main interest are estimates for ancestral eukaryotic groups (the oldest and simplest of these fossiles) in the International System of Units.
Other question of my interest are the same estimates of volume an mass for alive animals with radial symmetry. I apologize if my question bother some user of the site Biology Stack Exchange, I'm not a biologist. Wikipedia has the article Symmetry in biology, and I clarify that the approximations/estimates are for a typical specimen of the cited in this paragraph: alive animals with radial symmetry.
Question. Please provide estimates for the volume and the mass, of (most) ancestral multicellular organisms, and for the volume and the mass of a typical animal (of our geological epoch) with radial simmetry. Many thanks
I'm motivated to ask these questions after I read the book by Walter Álvarez , and inspired in a graphic, the Figure 2.1, that refers the book  by John D. Barrow. I know the Spanish editions of these books.
 Walter Álvarez, A Most Improbable Journey: A Big History of Our Planet and Ourselves, W. W. Norton & Company, (2016).
 John D. Barrow, The Constants of Nature, Jonathan Cape; 1st edition (2002).