28. Z1 and 2 2 are vertical angles. If mZ1 = (6x + 11)° and mZ2 = (10x – 9), find m21. mZ1 =​

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:

The shia sect of islam is primarily different from sunni islam in the belief that the first legitimate imam following muhammad was imam ali. unlike the three caliphs that succeeded muhammad, ali was part of muhammad's clan (related to him). major shia caliphates include the fatimid and safavid caliphates.  the answer will be option c. shia read more on