Where does LinQ store its IEnumerable selections?

char[] upperCase0 = { 'A', 'B', 'C', 'D' };
string[] upperCase = { "A", "B", "C", "D" };
string[] lowerCase = { "c","b","a"};

var iterB = from up0 in upperCase0
            from up in upperCase
            from low in lowerCase
            where Char.ToLower(up0).ToString() == low && low== up.ToLower()
            select new { up0, up, low };

List<Person> personList = new List<Person>()
{ 
    new Person() { Name="John", Age=32, Kids=2, Gender='M'},
    new Person() { Name="Ana", Age=28, Kids=3, Gender='F'},
    new Person() { Name="Mary", Age=42, Kids=2, Gender='F'},
    new Person() { Name="Jason", Age=33, Kids=1, Gender='M'},
    new Person() { Name="Mike", Age=22, Kids=0, Gender='M'}
};

var iterC = personList
    .Where(p => p.Age > 30)
    .OrderByDescending(p => p.Age)
    .Select(p => p.Name);