After the persian war, what did sparta, athens, and other greek communities collect to ward off future external attacks? slaves corn and other grains money resources for building walls

Here is your

Your answer is D resources for building walls.

Reason: If you wanted to protect yourself so no intruders will attack you you can collect resources to build a wall. Also its not A because slaves won't protect you from intruders its not B because corn and grain is used to feed people not to protect yourself from intruders and when it came down to rather C or D I choose D because with money you can buy the resources but money wouldn't protect you from intruders you will need a wall which includes money because you need money to buy resources but if you had just money it wouldn't really matter it would give the intruders another reason to rob or intrude on your land or property.

Your answer is D.