Give an example of your own of a scenario where it makes sense to use a concrete base class, an example where it makes sense to use an interface, and an example where it make sense to use an abstract base class.

Explain why memory usage may be a concern when running recursive functions.

Write the pseudocode for a recursive function that returns true if there is at least one true value in a list of booleans, false otherwise.

Write the pseudocode for a recursive function that returns the index of the first true value in a list of booleans if there is one, undefined otherwise.