It is "va" because the a in va represents he, she, and you (formal). He is going to the pool, so it is 'Mi padre va a la piscina con nosotros.'
Answer: I would probably say comer.
(Might be wrong though.)
Explanation:
This might be correct because comer is the only one that ends in -er.
“Hacer algo varias veces” is number 3
“Un condimento que no es muy dulce” is number 4
“Se usa para limpiar la boca” is number 1
And “la persona que sirve la comida en un restaurante” is number 2
Hope that helps!
Here is what I got as the answer:
Servir —> sirvió
