What is the Quds Force, the elite Iranian unit Israel has been targeting in airstrikes?

Source: Business Insider

Israel has attacked Iran's powerful Quds Force that trains and supports foes like Hamas and Hezbollah. Photo by Morteza Nikoubazl/NurPhoto via Getty ImagesThe Quds Force is an elite unit within Iran's Islamic Revolutionary Guards. It has been among the key targets of Israel's recent airstrikes.