Cogzidel Technologies interview question

1.Protocal /delegation /notification center /blocks/KVO 2.sqlite vs core data(no primary key) 3.autolayout / stackview / size class /type class 4.NSPushNotification(silent notification,message size,limit for each app) 5.Web Service(NSURLConnection,NSURLSessionDataTask,AFNetworking) 6.Categories vs Subclasses 7.cocopod