Yes, it's the boot loader. It also allows one to choose which operating
system to use if there is more than one.

A boot loader will need to be installed regardless of whether you're
dual booting, and grub is the default. But it's not like you have to do
anything special, since it occurs as part of the install process.

Other commenters are correct, but just fy:, you can set the grubloader timeout
to zero to skip the grub menu and jump straight to booting your OS once it is
installed.

See I told you it was the dumb question of the day..

YOU do not need to install grub. It is done for you. Grub is necessary
because each distribution has multiple options to boot from. Each kernel
gets a new line as does the recovery mode.