What is the world's largest source of surface water?

groundwater?

Explanation:

US and Canadian researchers recently calculated the total amount of the world's groundwater and estimated that it is equivalent to a lake 180 metres deep covering the entire Earth. This makes groundwater the largest active freshwater resource on the planet.

answer:

sequence 1- deletion

                  2- duplication

                  3- insertion

                  4- substitute

                  5- inversion

population. population is the number of people or animals in a particular place. an example of population is over eight million people living in new york city.

here is your answer hope i .