Answer:
Julio: ¿Y hay <u><em>personas</em></u> bonitas en la piscina?
Explanation:
This sentence could be completed with many nouns, which could be either concrete - people or objects - or even abstract, such as people's characteristics or actions.
As <em>bonitas </em>is the plural version of the feminine adjective <em>bonita </em>which means<em> pretty, </em>the noun also needs to be plural and feminine.
Therefore, Julio could either say:
¿Y hay <u><em>personas</em></u> bonitas en la piscina?
¿Y hay <u><em>boyas</em></u> bonitas en la piscina?
¿Y hay <u><em>actitudes</em></u> bonitas en la piscina?
Hope this helps! :)