Yes , you can use ArrayList for this.for exampleArrayList arryList1 = new ArrayList(); arryList1.Add(1); arryList1.Add("Two"); arryList1.Add(3); arryList1.Add(4.5);

yes you can with ArrayList

You can use ArrayList to have array with multiple data types. This is deprecated though, you can use generic list List which uses less memory and stable.

No

yes by the use of object array object[] arr=new object[10];