I would say that the fishes exhibited the greatest diversity (though the brachiopods also had considerable diversity) and mostly were of the ostracoderms (with a platey or shell-like skin and no jawbone) which exhibited many varieties and also the placoderm which had gills, a jawbone and fins so was developing characteristics of modern fish.
The answer to this question is the sacrum. The sacrum is a triangular bone that forms the base of the spinal column. This bone has a vital role in the skeletal system and also supports the weight of the upper body of a person and this bone and many nerves are inside the sacrum.
A cell wall, cytoplasm and ribosomes
<span>Luca Cavalli-Sforza is a geneticist who hypothesized that the skin-color change came late because previous people had complete vitamin D access to the foods that they are eating. But the moment they started farming, the main vitamin sources are reduced, making a larger gain of having light skin.</span>
