What Re marketing audiences cannot be defined by default?

A remarketing audience is a list of cookies or mobile-advertising IDs that represents a group of users you want to re-engage because of their likelihood to convert. You create remarketing audiences based on user behavior on your site or app, and then use those audiences as the basis for remarketing campaigns in your ad accounts like Google Ads and Display & Video 360. For example, you might create each of the following remarketing audiences and engage the users in them: Users who viewed product-detail pages, but didn’t add those items to their carts; Users who added items to their carts, but didn’t complete their purchases; Users who purchased items X and Y.