When I run sudo -s, my environment is preserved. However, when running a simple sudo <command> it appears not to be preserved.

The contents of my sudoers file:

mafro@ip-10-xx-xx-250:~ > sudo cat /etc/sudoers.d/mafro
Defaults env_reset
Defaults env_keep += "HOME"
mafro   ALL=(ALL)       NOPASSWD:ALL

Using sudo -s, the ll alias is available:

mafro@ip-10-xx-xx-250:~ > sudo -s
root@ip-10-xx-xx-250:~ > ll
total 8K
drwxrwxr-x  2 mafro dev 4.0K Jun  9 23:59 bin
drwxr-xr-x 20 mafro dev 4.0K Jun  9 23:59 dotfiles

Using straight sudo, it is not:

mafro@ip-10-xx-xx-250:~ > sudo ll
sudo: ll: command not found

What is happening here?