Answer: The underlined adjective that could also function as a verb is "gleaming".
Step-by-step explanation: The adjective "gleaming" is used to describe something as bright and shiny because it has been cleaned. However, "gleaming" can also function as a verb. Actually, as it ends in -ing, "gleaming" is the present participle and the gerund of the verb "gleam". "Gleam" means to reflect a bright light. Therefore, the meaning of the verb is very similar to the meaning of the adjective.