The head office has many connected subnetworks, so it will typically have adefault routeto forward traffic to the branch office (or external networks), since it may not need to define static routes for each branch network.

The branch office, which has only one subnetwork and a single connection to the head office, will have aspecific static routeto reach the head office subnet or other subnets at the head office, since it only needs to know the specific route to reach the head office's network.