Process Id generated by some other process

I guess the UID should be root for the PID generated by OS
a ps -ef should return all the current running processes and a ps -ef|grep <username> for a specific UID.

Yes but,Which process assigns this process id to processes? I am confused in that

hmm
it should be the init process ie the process ID 1
a 'pstree' should give you the cascading structure of parent child processes triggered and then when you do a 'ps -ef|grep init' bingo!
thats the root process which runs
for eg:

1.'pstree'
init─┬─NetworkManager─┬─dhclient
│ └─{NetworkManager}
├─acpid
├─atd
├─avahi-daemon───avahi-daemon
├─bluetoothd
├─bonobo-activati───{bonobo-activati}
├─console-kit-dae───63*[{console-kit-dae}]
├─cron
├─cupsd
├─2*[dbus-daemon]
├─dbus-launch
├─dd
├─evince───{evince}
├─fast-user-switc
├─firefox───9*[{firefox}]
├─gconfd-2
├─gdm───gdm─┬─Xorg
│ └─x-session-manag─┬─bluetooth-apple
│ ├─evolution-alarm───{evolution-alarm}
│ ├─gnome-keyring-d
│ ├─gnome-panel
│ ├─metacity
│ ├─nautilus
│ ├─nm-applet
│ ├─python
│ ├─seahorse-agent
│ ├─tracker-applet
│ ├─trackerd───2*[{trackerd}]
│ ├─update-notifier
│ └─{x-session-manag}
├─6*[getty]
├─gnome-keyring-d
├─gnome-power-man
├─gnome-screensav
├─gnome-settings-───{gnome-settings-}
├─gnome-terminal─┬─bash───pstree
│ ├─gnome-pty-helpe
│ └─{gnome-terminal}
├─gvfs-fuse-daemo───3*[{gvfs-fuse-daemo}]
├─gvfs-gphoto2-vo
├─gvfs-hal-volume
├─gvfsd
├─gvfsd-burn
├─gvfsd-trash
├─hald───hald-runner─┬─hald-addon-acpi
│ ├─hald-addon-cpuf
│ ├─hald-addon-dell
│ ├─hald-addon-inpu
│ └─hald-addon-stor
├─klogd
├─mixer_applet2───{mixer_applet2}
├─mount.ntfs
├─nm-system-setti
├─notification-da
├─pulseaudio─┬─gconf-helper
│ └─2*[{pulseaudio}]
├─syslogd
├─system-tools-ba
├─trashapplet
├─udevd
└─wpa_supplicant


2. ~/Desktop$ ps -ef |grep init
root 1 0 0 09:29 ? 00:00:01 /sbin/init
1000 6806 8978 0 22:26 pts/0 00:00:00 grep init