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.
The embryo thus enclosed in the egg finds its protection in the fact that it is encased in a fluid contained in the amnion. Superficial to it is the amnion, and below it is the yolk sac. In all the classes of amniotes these membranes (the amnion and the serolemma) develop in just the same fashion.