Which statement is true for all minerals? a. they have a crystalline structure. b. they contain useful metals. c. they are made of silicon and oxygen. d. they are too hard to be scratched with a nail.

Which statement about portugal is not true? a. it granted independence to its last colony in 1975 b. it has avoided conflict with spain c. it was a leader in european world exploration in the 1400s d. its economy is changing from agricultural to industrial b. it has avoided conflict with spain