The respiratory structures that terminate in a grape-like cluster are called alveoli.

Here's why:

* Alveoli: These tiny air sacs are the functional units of the lungs. They are responsible for the exchange of oxygen and carbon dioxide between the air we breathe and our bloodstream.

* Grape-like cluster: The alveoli are arranged in clusters, resembling a bunch of grapes. This arrangement provides a large surface area for gas exchange.

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