Macro colorer une ligne sur deux

Sub colore()
Dim Ligne As Long

For Ligne = 1 To 50
If Ligne Mod 2 = 0 Then Rows(Ligne).Interior.ColorIndex = 6
Next
End Sub

Sub aa()
Dim Plage As Range
Dim R As Range
Dim R2 As Range
If TypeName(Selection) <> "Range" Then Exit Sub
Set Plage = Selection
For Each R In Plage
  If R.Row Mod 2 = 0 Then
    If Not R2 Is Nothing Then
      Set R2 = Application.Union(R2, R)
    Else
      Set R2 = R
    End If
  End If
Next R
R2.Interior.Color = vbYellow
End Sub