Figure $2\mathrm{.}23$: Sample data for relation Ships $($use expression trees to solve g$,$h$,$i$)$

$!$ g$)$ Find the classes that had only one ship as a member of that class.

$!$ h$)$ Find those countries that had both battleships and battlecruisers.

$!$ i$)$ Find those ships that "lived to fight another day"; they were damaged in

one battle, but later fought in another.