Explain the statement that waves cause both constructive and destructive change to the shore line

Destructive: when waves wash up on beaches they drag pebbles with them when they draw back.

Constructive: as the waves wash up onto the beach they lose energy, thus they deposit any sediment/pebbles that they have.

Hope this helps. :)

The investiture controversy began as a power struggle between pope gregory vii (1072–85) and henry iv, holy roman emperor (1056–1106).[2] a brief but significant struggle over investiture also occurred between henry i of england and pope paschal ii in the years 1103 to 1107, and the issue played a minor role in the struggles between church and state in france, as well.by undercutting the imperial power established by the salian emperors, the controversy led to nearly 50 years of civil war in germany, and the triumph of the great dukes and abbots. imperial power was finally re-established under the hohenstaufen dynasty. historian norman cantor: