Difference between Domain Admins & Built-In Administrators Group ?

Hi,

I am new to AD and would like to seek your advice.

If a user (say Peter) is a member of the Built-In Administrators Group but not a member of the Domain Admins Group in Active Directory, does it mean that

1) Peter can still manage Domain Objects but with some limitations ?  What he cannot manage ?

2) Peter can remote access all workstations and servers in the Domain ?

Thanks