Which are older—sections of the interior or exterior great wall?

interior

Explanation:because the interior has to be build before they can build the outside so the interior has been around for a longer time then the exterior

answer: hey improve the marine life in a certain area.

they provide a new location for fishermen to fish and which works to ease the pressure on natural reefs.

they are a great way to get rid of large objects that would otherwise be placed on landfills

explanation:

answer; migrate from a region;