Why Descendants() and DescendantsAndSelf() returning same result? 

using System;
using System.IO;
using System.Linq;
using System.Xml.Linq;
using System.Collections.Generic;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            XElement ele = XElement.Load("Employees.xml");
            //IEnumerable<XElement> elements = ele.Descendants("City");
            IEnumerable<XElement> elements = ele.DescendantsAndSelf("City");

            foreach(var item in elements)
                Console.WriteLine(item);
        }
    }
}
//Output
/* 
<City>Acampo</City>
<City>Alta</City>
<City>Milford</City>
<City>Montara</City>
Press any key to continue . . .
*/

Employees.xml

<?xml version="1.0" encoding="utf-8" ?>
<Employees>
 <Employee>
    <EmpId>1</EmpId>
    <Name>Sam</Name>   
    <Sex>Male</Sex>
    <Phone Type="Home">423-555-0124</Phone>
    <Phone Type="Work">424-555-0545</Phone>
   <Address>
      <Street>7A Cox Street</Street>
      <City>Acampo</City>
      <State>CA</State>
      <Zip>95220</Zip>
      <Country>USA</Country>
    </Address>
 </Employee>
 <Employee>
    <EmpId>2</EmpId>
    <Name>Lucy</Name>
    <Sex>Female</Sex>
    <Phone Type="Home">143-555-0763</Phone>
    <Phone Type="Work">434-555-0567</Phone>
    <Address>
      <Street>Jess Bay</Street>
      <City>Alta</City>
      <State>CA</State>
      <Zip>95701</Zip>
      <Country>USA</Country>
    </Address>
 </Employee>
 <Employee>
    <EmpId>3</EmpId>
    <Name>Kate</Name>
    <Sex>Female</Sex>
    <Phone Type="Home">166-555-0231</Phone>
    <Phone Type="Work">233-555-0442</Phone>
    <Address>
      <Street>23 Boxen Street</Street>
      <City>Milford</City>
      <State>CA</State>
      <Zip>96121</Zip>
      <Country>USA</Country>
    </Address>
 </Employee>
 <Employee>
    <EmpId>4</EmpId>
    <Name>Chris</Name>
    <Sex>Male</Sex>
    <Phone Type="Home">564-555-0122</Phone>
    <Phone Type="Work">442-555-0154</Phone>
    <Address>
      <Street>124 Kutbay</Street>
      <City>Montara</City>
      <State>CA</State>
      <Zip>94037</Zip>
      <Country>USA</Country>
    </Address>
 </Employee>
</Employees>