I am trying to understand various points of the programme listed below and
given in a book as an example (I have deleted some of the lines of code not
necessary to this question, and commented some of the lines – the original
had no commenting):-

Private Sub Worksheet_Change(ByVal Target As Excel.Range)
   Dim VRange As Range, cell As Range
   Dim Msg As String
   Dim ValidateCode As Variant        ‘returns TRUE or text string
   Set VRange = Range("InputRange")    ‘InputRange is defined area on spread
sheet
   For Each cell In Target
       If Union(cell, VRange).Address = VRange.Address Then    ‘is the cell in
InputRange
           ValidateCode = EntryIsValid(cell)
           If ValidateCode = True Then
               Exit Sub
           Else
        ‘This outputs message of reason not valid entry
           End If
       End If
   Next cell
End Sub

Private Function EntryIsValid(cell) As Variant
     '   Returns True if cell is an integer between 1 and 12 or blank
     '   Otherwise it returns a string that describes the problem
     ‘   i.e. entry is Text, > 12 or Not an Intiger
End Function

My queries are
1.    Why the line     Set VRange = Range("InputRange"),     why not use the
expression     Range("InputRange") ?
2.    Why       For Each cell in Target,     when sub routine gives only one
cell reference?