Wind occurs when air masses
move from one place to
another. what causes the
movement of air masses?

air moves because of two reasons..
1 temperature difference
2 pressure difference

1 temperature difference :
 when there is temperature difference in the atmosphere ,,hot air rises and cold air takes its place ... so movement of air occurs..
2 pressure difference:
also when there is pressure difference in atmosphere ,, air moves away from the area where there is more pressure..
if there is no temperature and pressure difference then air will not move...

Its decreasing because of illnesses

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: