The Illinois state sales tax rate is 6.25%, and the average IL sales tax after local surtaxes is 8.19%. Counties and cities can charge an additional local sales tax of up to 3.5%, for a maximum possible combined sales tax of 9.75%.
(clue: look up Hirschsprung's disease.) The first important step in development of the digestive system occurs during folding of the embryonic disc as neurulation takes place (weeks 4 and 5) - the thin endodermal layer is gathered up' inside the embryonic body to form a tubular structure. Gut tube, respiratory diverticulum, yolk sac, and allantois.
It is not a primary germ layer but in the embryo is amoeboid and can become any layer. It is like adult connective tissue which makes up the bulk of the body. Since changes move from anterior to posterior, the oldest part of the section is anterior. Model #22 shows a dorsal, tubular nerve chord.