Answer: Pulldown menus
Step-by-step explanation:
Pulldown menus refer to the graphical control element, that is identical to a list box, which enables user to be bake to select one value from a list.
They're regarded as the menu of options that will appear when an item is selected with a mouse. In this case, the item that the user selected will show at the top of the display screen, while the menu appears will show below it.
Therefore, Alex should use the pulldown menus to hide the long list of hypertext links so that it appears only in response to a tap of a major heading in the navigation list.