What is the topography of the shield like

Drag and drop a statement or reason to each box to complete the proof. statement reason △abc , de⎯⎯⎯⎯⎯∥ac⎯⎯⎯⎯⎯ given corresponding angles postulate △bde∼△bac babd=bcbe polygon similarity postulate ba=bd+dabc=be+ec bd+dabd=be+ecbe substitution property of equality bdbd+dabd=bebe+ecbe addition of fractions 1+dabd=1+ecbe simplify. dabd=ecbe subtraction property of equality

The european union was formally established in

What is the border between layers a through f and layer g called?