Which process causes delta formation

Can someone list any possible solutions to air pollution ?

Alow-pressure belt means the air is cold and dry warm and rising cold and sinking warm and moist

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