How were American and British paratroopers helpful during the D-Day landings?

The D-Day invasion began with a dangerous attack by American paratroopers. Dropped behind enemy lines to soften up the German troops and to secure needed targets, the paratroopers knew that if the accompanying assault by sea failed — there would be no rescue.

Explanation:

answer; eliminate parking problems in cities, because a car took up only half as much space as a horse and buggy;

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.