Define diastrophism and give examples

An earthquake’s epicenter can be determined from arrival time data recorded on a(

Which statement explains what upwelling causes? a. upwelling causes tides to rise and fall. b. upwelling causes changes in the direction of currents. c. upwelling causes nutrients, minerals, and tiny organisms to rise. d. upwelling causes currents in the pacific ocean to change direction. i think the answer is c.

Given: circle a externally tangent to circle b. how many possible common tangents to circles a and b can exist? 2 3 4