has the following array:  $arr = ["abc"," ABC", 0.23, "Begin"," oh", 11,456, "sort"," EMAIL"] ; 
 Why is it sorted using  sort ($arr), sort ($arr, SORT_STRING), sort ($arr, SORT_NUMERIC)  respectively? 
["ABC","Begin","EMAIL","abc","oh","sort",0.23,11,456]
["abc","ABC","Begin","oh","sort","EMAIL",0.23,11,456]
[0.23,11,456,"ABC","Begin","EMAIL","abc","oh","sort"]