What happens to the dirt and matrix from each grid? it is discarded as trash it is burned to avoid contamination of the site it is collected for further analysis it is put back in the grid after the fossils have been removed?

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands