... a reference as a thread attached to a variablePassing by ReferenceIn PHP, the & symbol, when prefaced to a variable, tells the parser to pass a reference to the variable’s value, not the ... PHP to pass the variables’references only.Now the variables $n1, $n2, and $n3 are attached to “threads” that lead to the values of $a1 , $a2 , and $a3 . In other words, there is one group of values, ... two sets of variablenames are allowed to access them.Therefore, the function fix_names only has to assign new values to $n1, $n2, and $n3 to update the values of $a1 , $a2 , and $a3 . The output...